Answer:
Explanation:
Beryllium especially, but Boron as well both exhibit metallic characteristics.
The outside ring of Beryllium contains 2 electrons. It would have to take on 6 electrons to have a ring of 8. The same statement can be made about Boron (except that it would need 5 electrons to make 8). It is easier for the atom to give up 2 or 3 than than to take on 5 or 6. It would not be easy to have a 5 or 6 minus charge on it.
Boron and beryllium are exceptions to the octet rule because they have less than eight electrons in their valence shell in some compounds, such as BF₃ and BeH₂, due to their position in Group III and the unique properties of their electrons.
Boron and beryllium are exceptions to the octet rule because they do not always complete an octet of electrons in their compounds. Boron, found in compounds like BF₃, tends to form compounds with only six valence electrons around the boron atom, rather than the eight suggested by the octet rule. Beryllium, on the other hand, often ends up with only four valence electrons as seen in the molecule BeH₂. These deviations from the octet rule occur because of the elements' positions in Group III of the periodic table, where elements commonly have fewer valence electrons than required to fulfill the octet. Thus, compounds of these elements are less predictable from the octet rule, which was primarily based on observations of the elements in Groups IV through VIII.
Incomplete octets are found in some compounds involving boron, aluminum, and beryllium, such as boron hydrides. The behavior of these elements is based on their tendency to form stable structures with fewer than eight electrons; boron atoms, for example, might follow a 'sextet rule' in some compounds but can achieve full octets in others like in its complex with ammonia, NH₃BF₃. Likewise, beryllium typically forms molecular compounds wherein it forms single covalent bonds without reaching an octet, due to its limited number of valence electrons and its small atomic size.
Hydrogen gas and oxygen gas react to form liquid hydrogen peroxide. Which statement is true about the reaction? A. The same atoms are present, so the chemical properties remain the same. B. The atoms of the reactants combine to form a new substance. C. The two gases mix together, but a new substance does not form. D. The product that is formed has the same physical properties as the reactants.
Final answer:
The correct answer to the question is B. The atoms of the reactants combine to form a new substance, and in the case of hydrogen and oxygen gases, they react to form liquid hydrogen peroxide with different chemical properties.
Explanation:
When hydrogen gas and oxygen gas react to form liquid hydrogen peroxide, the atoms of the reactants combine to form a new substance. This is because a chemical reaction involves the rearrangement of atoms to produce new substances with different chemical properties.
The correct statement about this reaction is: B. The atoms of the reactants combine to form a new substance. In a chemical reaction such as this, the physical and chemical properties of the products are typically different from those of the reactants.
An example of a simple chemical reaction is the decomposition of hydrogen peroxide into water and oxygen.
This reaction can be represented by the balanced equation 2H₂O₂ (hydrogen peroxide) → 2H₂O (water) + O₂ (oxygen), showing that hydrogen peroxide and water are compounds composed of more than one type of element, while molecular oxygen is a homonuclear molecule but not a compound
PLEASE HELP!
Match the action to the effect on the equilibrium position for the reaction N2(g) + 3H2(g) ⇌ 2NH3(g).
Match Term Definition
1.) Decreasing the pressure A) Shift to the left
2.) Adding hydrogen gas B) Shift to the right
3.) Adding a catalyst C) No effect
May someone help me match these definitions?
Answer:
1) Increasing the pressure A) Shift to the left
2) Removing hydrogen gas B) Shift to the right
3) Adding a catalyst C) No effect
Explanation:
Le Châtelier's principle states that when there is an dynamic equilibrium, and this equilibrium is disturbed by an external factor, the equilibrium will be shifted in the direction that can cancel the effect of the external factor to reattain the equilibrium.1) Decreasing the pressure:
When there is an increase in pressure, the equilibrium will shift towards the side with fewer moles of gas of the reaction. And when there is a decrease in pressure, the equilibrium will shift towards the side with more moles of gas of the reaction.The reactants side (left) has 4.0 moles of gases and the products side (right) has 2.0 moles of gases.So, decreasing the pressure will shift the reaction to the side with more moles of gas (left side).so, the right match is: A) Shift to the left.
2) Adding hydrogen gas:
Adding hydrogen gas will increase the concentration of the reactants side, so the reaction will be shifted to the right side to suppress the increase in the concentration of hydrogen gas by addition.so, the right match is: B) Shift to the right.
3) Adding a catalyst:
Catalyst increases the rate of the reaction without affecting the equilibrium position.Catalyst increases the rate via lowering the activation energy of the reaction.This can occur via passing the reaction in alternative pathway (changing the mechanism).The activation energy is the difference in potential energies between the reactants and transition state (for the forward reaction) and it is the difference in potential energies between the products and transition state (for the reverse reaction).in the presence of a catalyst, the activation energy is lowered by lowering the energy of the transition state, which is the rate-determining step, catalysts reduce the required energy of activation to allow a reaction to proceed and, in the case of a reversible reaction, reach equilibrium more rapidly.with adding a catalyst, both the forward and reverse reaction rates will speed up equally, which allowing the system to reach equilibrium faster.so, the right match is: B) No effect.
When a constraint is imposed on a reaction system in equilibrium, the equilibrium position will change in order to annull the constraint.
What is equilibrium?A reaction is said to have attained dynamic equilibrium when the rate of forward reaction is equal to the rate of reverse reaction. We know that when a constraint is imposed on a reaction system in equilibrium, the equilibrium position will change in order to annull the constraint.
Now the effect of the factors stated on the equilibrium position is matched below;
Increasing the pressure ------ > Shift to the right
Removing hydrogen gas -------> Shift to the left
Adding a catalyst ----------> No effect
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An inflatable toy starts with 1.05 moles of air and a volume of 5.17 liters. When fully inflated, the volume is 8.00 liters. If the pressure and temperature inside the toy don’t change, how many moles of air does the toy now contain? A. 2.05 mol B. 1.62 mol C. 1.55 mol D. 0.679 mol
Answer:
1.625 mol.
Explanation:
To calculate the no. of moles of a gas, we can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant.
T is the temperature of the gas in K.
If P and T is constant, and have two different values of (n and V):n₂V₁ = n₁V₂
n₁ = 1.05 mole, V₁ = 5.17 L.
n₂ = ??? mole, V₂ = 8.0 L.
∴ n₂ = n₁V₂/n₂ = (1.05 mole)(8.0 L)/(5.17 L) = 1.625 mol.
The toy now contains 1.62 mol
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*URGENT*
Which of the following is true about an ionic compound?
a. the chemical formula shows the atoms in a molecule
b. the formula unit gives the number of each type of ions in a crystal
c. it is composed of anions and cations and yet it is electronically neutral
d. the chemical formula shows the ions in a molecule
Your answer would be D
Statement which is true about ionic compounds is that it is composed of anions and cations and yet it is electrically neutral.
What is an ionic compound?
Ionic compound or electrovalent compound is a type of compound which is formed between two elements when there is an exchange of electrons which takes place between the atoms resulting in the formation of ions.
When the atom looses an electron it develops a positive charge and forms an ion called the cation while the other atom gains the electron and develops a negative charge and forms an ion called the anion.
As the two atoms are oppositely charged they attract each other which results in the formation of a bond called the ionic bond and the compound possessing the bond is called the ionic compound.
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A 1.00 L volume of HCl reacted completely with 2.00 L of 1.50 M Ca(OH)2 according to the balanced chemical equation below. 2HCl + Ca(OH)2 CaCl2 + 2H2O What was the molarity of the HCl solution? 0.375 M 1.50 M 3.00 M 6.00 M
Answer:
[tex]\boxed{\text{6.00 mol/L}}[/tex]
Explanation:
(a) Balanced equation
2HCl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O
(b) Moles of Ca(OH)₂
[tex]\text{Moles of base} = \text{2.00L} \times \dfrac{\text{1.50 mol}}{\text{1 L}} = \text{3.000 mol base}[/tex]
(c) Moles of HCl
[tex]\text{Moles of HCl} = \text{3.000 mol base} \times \dfrac{ \text{2 mol HCl}}{\text{1 mol base}} = \text{6.000 mol HCl}[/tex]
(d) Molar concentration of HCl
[tex]\text{Molar concentration} = \dfrac{\text{moles of solute}}{\text{litres of solution}}\\\\c = \dfrac{ n }{ V}\\\\c= \dfrac{ \text{6.000 mol}}{ \text{1.000 L}} = \text{6.00 mol/L}[/tex]
The molar concentration of the HCl was [tex]\boxed{\textbf{6.00 mol/L}}[/tex]
If force is held constant as surface area decreases pressure
Pressure, defined as the normal force per unit area, increases when the surface area decreases while the force is constant. This is based on the equation of pressure (P=F/A) and can be largely observed in fluid dynamics, for instance, within conduits with decreasing cross-sectional areas.
Explanation:Pressure is defined as the normal force per unit area exerted on a surface by a fluid or gas, or the force exerted perpendicularly on a surface. An important characteristic of pressure is that it acts uniformly in all directions at a single point in a fluid. This is also known as Pascal's Principle.
According to the equation P=F/A, where P is pressure, F is the force, and A is the area, pressure increases when surface area decreases, given that the force is held constant. This is simply because as the denominator in a fraction decreases, the overall value of the fraction increases. Therefore, if the surface area decreases with a constant force, the pressure consequently increases.
The phenomenon can be observed largely in fluid dynamics. For example, in pipes or any other fluid-carrying conduits where the cross-sectional area decreases, the pressure tends to increase due to the conservation of the flow rate (continuity equation). When the tube narrows, fluid speed increases and pressure decreases. Similarly, a decrease in the area of a compressed gas container while keeping the force (temperature) constant results in the compression of gases, thereby increasing their pressure.
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2Fe(s) + O2(g) → 2FeO(s)
To which category does this reaction belong?
Answer:
Redox reactions
Explanation:
Redox reactions consists of both oxidation and reduction
one species gets oxidised and other species become reduced, both oxidation and reduction happen simultaneously
reduction is either gain of electrons or gain of hydrogen. in reduction the oxidation number of species reduces
in this reaction the reduction half equation is
O₂ + 4e --> 2O²⁻
oxidation is either loss of electrons or gain of oxygen. in oxidation the oxidation number of species increases.
Fe --> Fe²⁺ + 2e
since both these half reactions happen overall its a redox reaction
Explain why aldehydes and ketones react with a weak acid such as hydrogen cyanide but do not react with strong acids such as hcl or h2so4 (other than being protonated by them).
Answer:
The cyanide ion is a strong nucleophile.
Explanation:
Strong acids
Strong acids like hydrochloric and sulfuric acid dissociate completely in solution.
[tex]\underbrace{\hbox{HCl }}_{\hbox{strong acid}} + {\text{ H$_{2}$O }} \longrightarrow \text{H}_{3}\text{O}^{+}+ \underbrace{\hbox{Cl^{-}}}_{\hbox{weak nucleophile}}[/tex]
Because they are strong acids, their conjugate bases are extremely weak bases/nucleophiles.
Thus, they can protonate the carbonyl oxygen, but the conjugate bases cannot act as nucleophiles.
Weak acids
Weak acids like HCN dissociate only slightly in solution.
[tex]\underbrace{\hbox{HCN}}_{\hbox{weak acid}} + {\text{ H$_{2}$O }} \rightleftharpoons \text{H}_{3}\text{O}^{+}+ \underbrace{\hbox{:CN^{-}}}_{\hbox{strong nucleophile}}[/tex]
Because HCN is a weak acid, its conjugate base is a strong nucleophile.
Thus, it generates relatively few hydronium ions, but the cyanide ion is a strong nucleophile that can attack the partially positive carbon and form the cyanohydrin.
RCH=O + CN⁻ ⟶ RCH(CN)O⁻ ⟶ RCH(CN)OH
As the CN⁻ ions react with the aldehyde or ketone, they are removed from solution.
According to Le Châtelier's Principle, more HCN dissociates to replace the CN⁻ ions, and the reaction goes nearly to completion.
Aldehydes and ketones react with hydrogen cyanide because it provides cyanide ions that act as nucleophiles in a nucleophilic addition reaction to form cyanohydrins; strong acids don't provide such nucleophiles and instead only protonate the carbonyl group.
Explanation:The reason why aldehydes and ketones react with a weak acid like hydrogen cyanide (HCN) but not with strong acids such as HCl or H2SO4 lies in the mechanism of nucleophilic addition reactions. In the presence of a strong acid, the carbonyl group of aldehydes or ketones is protonated, making the carbon even more electrophilic but without providing a good nucleophile. HCN, being a weak acid, partially dissociates in the presence of a strong base to form cyanide ions (CN-), which are good nucleophiles and can attack the carbonyl carbon to form cyanohydrins. The reaction requires slightly acidic conditions (pH around 4-5) to optimize the rate, as too much strong acid would suppress the producing of cyanide ions necessary for the nucleophilic addition.
Aldehydes and ketones react with weak acids like hydrogen cyanide (HCN) because they can form cyanohydrins through nucleophilic addition reactions. In this reaction, the weak acid HCN is converted into the cyanide ion (CN-) by a small amount of a strong base. The cyanide ion then attacks the carbonyl carbon of the aldehyde or ketone, resulting in the formation of a cyanohydrin. This reaction requires a basic catalyst and is favored for aldehydes and unhindered ketones.
The requirement that a reversible reaction be at equilibrium is that:
A,the concentrations on the two sides of the arrow be equal
B.the velocity for the forward reaction equal that of the reverse reaction
C.there will be as many molecules of the substances on one side of the arrow as
there are molecules of the substances on the other side
D.the moles of products will equal the moles of reactants
Answer:
B.the velocity for the forward reaction equal that of the reverse reaction
Explanation:
A state of rest or motion of a system is described as equilibrium.
For a system to be in equilibrium, the following conditions must be met:
1. It must be involved in reversible chemical process no matter how small the extent of the reversibility.
2. The rate of forward process is equal to the rate of backward or reverse process.
3. The system must be closed.
4. There is no change in the concentration of each of the species in equilibrium with respect to time. There must be a constancy of concentration of each species in the equilibrium process.
When we change any of the conditions of equilibrium, the Le Chatelier's principle comes into play.
The principle states that "if any of the conditions of a system in equilibrium is changed, the system will adjust itself in order to annul the effect of the change".
Answer:
B.the velocity for the forward reaction equal that of the reverse reaction
Explanation:
A reversible reaction proceeds in a closed system. Equilibrium is only attainable in a closed system. When a reaction occurring in a closed system attains equilibrium, the rate(velocity) of the forward reaction will be exactly the same as the rate (velocity) of the reverse reaction.
This implies that the forward and reverse reactions proceed at the same rate.
How many amperes would be needed to produce 60.0 grams of magnesium during the electrolysis of molten mgcl 2 in 2.00 hours?
Answer:
[tex]\boxed{\text{66.2 A}}[/tex]
Explanation:
1. Write the equation for the reaction.
M_r: 24.30
MgCl₂ ⟶ Mg + Cl₂
m/g: 60.0
2. Calculate the moles of Mg
Moles of Mg = 60.0 g Mg × (1 mol Mg/ 24.30 g Mg) = 2.469 mol Mg
3. Calculate the moles of electrons
Moles of electrons = 2.469 mol Mg × (2 mol electrons/1 mol Mg)
= 4.938 mol electrons
4. Calculate the number of coulombs
Q = 4.938 mol electrons × (96 485 C/1 mol electrons) = 476 500 C
5. Calculate the current required
Q = It
I = Q/t
t = 2.00 h × (60 min/1h) × (60 s/1 min) = 7200 s
I = 476 500 C/7600 s= 66.2 C/s = 66.2 A
You need a current of [tex]\boxed{\textbf{66.2 A}}[/tex].
what is the name of this compound? see attached.
a) phenylhyde
b) benzaldehyde
c) phenol aldehyde
d) cyclohexylhyde
The answer is B.) benzaldehyde sorry if I’m wrong
Answer: Option (b) is the correct answer.
Explanation:
In the given structure a benzene molecule, that is, [tex]C_{6}H_{5}[/tex] is attached. And, further an aldehyde group that is, CHO group is attached to the benzene molecule.
Hence, suffix "aldehyde" will be added to the name of this molecule.
Whereas a group with formula [tex]C_{6}H_{5}OH[/tex] is known as phenol.
Therefore, we can conclude that the name of this given compound is benzaldehyde.
Balance this nuclear reaction by supplying the missing nucleus.?249/98Cf + ____ -----> 257/104Rf + 4 1/0n
Answer:
The missing nucleus is carbon-12:
[tex]^{12}_6C[/tex]Explanation:
The nuclear reaction given is:
[tex]^{249}_{98}Cf[/tex] + ___ → [tex]^{257}_{104}Rf+4^1_0n[/tex]
To balance this equation you must add a nucleus which contains the missing mass and atomic numbers.
Mass number is the number of protons plus neutrons and is the superscript to the left of the chemical symbol: 249 for Cf, 257 for Rf, and 1 for n (neutron).
Atomic number is the number of protons and is the subscript to the left of the chemical symbol: 98 for Cf, 104 for RF and 0 for n.
Thus, the balance is:
Mass number:
249 + A = 257 + 4 × 1249 + A = 257 + 4249 + A = 261A = 261 - 249A = 12Atomic number:
98 + Z = 104 + 4×098 + Z = 104Z = 104 - 98Z = 6Then, you are looking for a nucleus (or gropu of nuclei) which supply 6 protons and 6 neutrons. That is a nucleus of carbon-12: [tex]^{12}_6C[/tex].
The balanced nuclear reaction is:
[tex]^{249}_{98}Cf+^{12}_{6}C[/tex] → [tex]^{257}_{104}Rf+4^1_0n[/tex]
The question is about balancing a nuclear equation. The missing nucleus in the nuclear reaction 249/98Cf + ____ -----> 257/104Rf + 4 1/0n is Carbon-8 (8/6C) determined by conserving atomic number and atomic mass.
Explanation:The problem you have is a nuclear equation specifically a type of nuclear reaction called alpha decay, where an element transforms into a new element and emits an alpha particle. In your problem Californium-249 (249/98Cf) decays into Rutherfordium-257 (257/104Rf) and four neutrons (1/0n). So in order to balance the nuclear equation we need to find out which nucleus reacts with Californium-249 to produce Rutherfordium-257 and four neutrons.
This can be done by looking at the difference in the atomic numbers and atomic masses on either side of the equation. We know that the atomic number (the number of protons) and atomic mass (the number of protons + neutrons) must be conserved during a nuclear reaction.
Here the atomic number goes from 98 on the left side of the equation (the Californium) to 104 on the right side (the Rutherfordium). Therefore, the difference 6 is the atomic number of the missing nucleus. The atomic mass goes from 249 (Californium) to 257 (Rutherfordium) so the difference 8 is the atomic mass of the missing nucleus. Thus, the missing nucleus is Carbon-8, or 8/6C.
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_____?or current flow, can be thought of as a faucet being turned on and water flowing.
a. Circuit flow
b. Electrical resistance
c. Voltage
d. Amperage
Final answer:
Amperage or current flow, can be thought of as a faucet being turned on and water flowing. Option d
Explanation:
The correct answer to the student's question is d. Amperage. The analogy of a faucet turning on and water flowing is used to describe electric current. Electric current can indeed be thought of similarly to water flowing through a pipe for its easy visualization. When we talk about the flow of charge in a circuit, we use the term amperage to quantify it.
The SI unit for electric current, or amperage, is the ampere, which is defined as one coulomb of charge passing through a point in one second (1A = 1C/s).
This means that electric current, or amperage, is the rate at which the electrical charge is flowing. In electric circuits, this is akin to water moving through a piping system, where the current is the same at all points in the circuit, including inside any batteries or resistors.
This flow of charge is crucial for the functioning of electrical appliances and is measured and regulated for safety and efficiency using devices like fuses and circuit breakers which are rated in amperes. Option d
Entropy decreases when select one:
a. pressure decreases.
b. temperature decreases.
c. the system is agitated.
d. temperature increases.
It is B. What I found is when water freezes it's entropy decrease. If water freezing that means the temperature is decreasing and that is B.
What does it mean to discuss the concentration of a solution
When you are discussing the concentration of solution, you are discussing how many particles there are in a given amount of solvent. You are comparing. If there is more solute in a beaker of solvent, then it is highly concentrated. If there is less solute in a beaker of the same amount of solvent, then it is less concentrated or more dilute. The terms diluted and concentrated are related to each other. These words are used to compare certain solutions to each other, since there is nothing like numbers, these words are relative to one another.
Final answer:
Discussing the concentration of a solution means specifying the exact amount of solute dissolved in a given amount of solvent. It can be expressed as a mass percentage, ppm, or ppb, and is important for understanding solution strength and stoichiometry in chemical reactions.
Explanation:
To discuss the concentration of a solution means to specify the amount of solute that is dissolved in a given volume or mass of solvent. Descriptive words like dilute or concentrated provide a general idea but actual measurements of concentration give precise meaning. For instance, a solution with a high concentration has a large amount of solute relative to the solvent. Conversely, a solution with a low concentration has a smaller amount of solute. People familiar with making instant coffee or lemonade inherently understand this concept; too much powder results in a strong flavor, whereas too little leaves the solution weak and watery.
Concentration can be quantified in several ways, such as mass percentage, parts per million (ppm), and parts per billion (ppb). A common method is by stating the ratio of the mass of the solute to the total mass of the solution. This is vital in chemistry, especially for controlling reactions and understanding the stoichiometry of reactants in solutions.
a mixture of oxygen, nitrogen and hydrogen gases exerts a total pressure of 85 kpa at 0 degrees Celsius .The partial pressure of the oxygen is 20 kpa and the partial pressure of the nitrogen is 50 kpa .What is the partial pressure of the hydrogen gas in this mixtures ?
Answer:
15 kPa.
Explanation:
The total pressure of a mixture of gases can be defined as the sum of the pressures of each individual gas:Ptotal = P1 + P2 + … + Pn.
∴ Ptotal = P of oxygen + P of nitrogen + P of hydrogen.
∴ P of hydrogen = P total - (P of oxygen + P of nitrogen) = 85 kPa - (20 kPa + 50 kPa) = 15 kPa.
Which of the following is a force? A. mass B. volume C. weight D. length
I believe it’s C......
it should be c <3 lol hahahahaahaa
The transfer of energy as heat caused by the collision of molecules is called
Answer:
The transfer of energy as heat caused by the collision of molecules is called conduction.Explanation:
The transfer of energy as heat, i.e. heat transfer, is the transfer of kinetic energy due to difference in temperatures of the bodies: heat is transferred from warmer objects to cooler obects.
This heat transfer may occur by three different means:
conduction,convection, andradiation.Conduction is the transfer of heat between objects in direct contact and is due to the transfer of kinetic energy among neighbour particles (atoms or molecules) which are in constant vibration and colliding one to each other. The hotter particles are vibrating faster than the cooler ones, and, so, during the collisions the faster particles trasfer kinetic energy to the quiter particles.
For example, when you heat the tip of a needle the heat will be transfered from the tip to the rest of the needle by conduction.
Convection is the transfer of heat by the motion of fluids (gases or liquids), again the hotter particles, which have greater kinetic energy, transfer their energy to the cooler particles, but in this case the fluid moves.
Radiation is the heat transfer by electromagnetic waves; again from hotter objects to cooler ones. Since electromagnetic waves travel through vacumm, radiation does not need a physical medium.
Conduction is the process by which energy is transferred as heat through the direct contact of molecules, facilitated by atomic or molecular collisions due to differing temperatures. This transfer of heat can change the temperature, affecting things from everyday life to global weather, demonstrating the essential role of conduction in understanding our world.
Explanation:The process of energy being transferred as heat through the collision of molecules is called conduction. Conduction is a fundamental concept in physics and it involves the direct transmission of heat through a substance due to a difference in temperature. It is facilitated by atomic or molecular collisions and it occurs when there is a connection or contact surface between high temperature and low temperature regions.
For example in Figure 1.21 it illustrates how molecules, each having different kinetic energies resulting from their respective temperatures, collide and transfer energy. A molecule in the lower-temperature region gains energy after the collision while a molecule in the higher-temperature region loses energy.
This transfer of heat might change the temperature and is a central concept in thermodynamics playing a critical role in everything from everyday cooking to industrial processes. Therefore understanding conduction is essential to understanding the world around us, from weather patterns on Earth to the life cycle of stars.
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A pesticide is used to kill crops in a field. A scientist wants to learn how the pesticide is affecting the plants and animals near the field. Which procedure would be most useful? measuring the radioactivity of a sample of untreated pesticide introducing a radioactive tracer to common compounds in the soil subjecting the pesticide to neutron activation analysis introducing a radioactive tracer into a sample of pesticide
Answer:
introducing a radioactive tracer into a sample of pesticide
Explanation:
introducing a radioactive tracer into a sample of pesticide
Gina is driving her car down the street. She has a teddy bear sitting on the back seat. A dog runs in front of Gina's car, so she quickly applies the brakes. The force of the brakes causes the car to stop, but the teddy bear continues to move forward until it hits the car's dashboard. The teddy bear did not stop at the same time as the car because A. objects in motion tend to stay in motion unless acted upon by an outside force. B. only objects touching the Earth's surface can be acted upon by an outside force. C. more force is required to stop softer objects than to stop harder objects. D. objects in motion can only be stopped by the application of a balanced force.
object in motion tends to be in motion unless acted upon by an external force
Answer:
The answer is A) objects in motion tend to stay in motion unless acted upon by an outside force
Explanation:
Newton's laws of motion are three laws that describe the relationship between forces acting on an object and the motion of that object. Newton's first law of motion states that an object that is at rest or in uniform motion tends to stay at rest or in uniform motion, respectively, until acted upon by an outside force.
Chemical hazards are defined as: A. Parasites in food B. Poisonous substances that occur naturally or are accidentally added during food handling C. Germs or pathogens entering food D. Foreign objects falling into food
Answer:
B. Poisonous substances that occur naturally or are accidentally added during food handling.
Explanation:
A chemical hazard is defined as the harmful substance that causes loss or harm to the society or community at large and it can be man-made or naturally induced. Such as the hazard which is found of the food can lead to food poisoning or unnatural death. If consumed accidentally or by naturally occurring or added by the process of food handling can cause the loss of digestive power and may lead to food benign prey to the foreign substances that are toxic or untreated.Chemical hazards are poisonous substances that occur naturally or are accidentally added during food handling. They can cause foodborne illnesses and include toxins produced by bacteria or fungi, pesticides, heavy metals, and other harmful chemicals.
Chemical hazards are defined as poisonous substances that occur naturally or are accidentally added during food handling. These hazards can include toxins produced by bacteria or fungi, pesticides, heavy metals, and other harmful chemicals. When these substances contaminate food and are ingested, they can cause foodborne illnesses. For example, aflatoxins are toxic and carcinogenic compounds released by fungi that can contaminate nuts and grains.
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A solution of ammonia has a pH of 11.8. What is the concentration of OH– ions in the solution? Useful formulas include , , , and . 1.58 10–12 M 6.31 10–3 M 2.20 M 158 M
Answer:
The concentration of OH- ions = 6.31*10⁻³M
Explanation:
Given:
pH of ammonia solution = 11.8
Formula:
[tex]pH + pOH = 14\\\\pOH = 14-pH = 14 - 11.8 = 2.2\\\\pOH = -log[OH-]\\[/tex]
[tex][OH-] = 10^{-pOH } = 10^{-2.2} = 6.31*10^{-3} M[/tex]
The concentration of OH- ions in a solution with a pH of 11.8 is 6.31 times 10⁻³ M. The calculation involves finding the pOH and then the antilog of the negative pOH.
The pH of a solution is a measure of its acidity or basicity. For a solution with a pH of 11.8, we can find the concentration of hydroxide ions (OH-) by first calculating the pOH, which is 14.00 (at 25°C) minus the pH value. Therefore, the pOH is 14.00 - 11.8 = 2.2. The concentration of OH- is then found by taking the antilog (base 10) of the negative pOH: [OH-] =[tex]10^{ -pOH }[/tex]= 10⁻²°².
To calculate this, we get 10⁻²°² = 6.31 times 10⁻³ M, meaning the concentration of OH- in the solution is 6.31 times 10⁻³M.
If an aqueous solution of a soluble ionic com- pound is made, it will usually
1. become a ductile solid.
2. become covalent.
3. form an insoluble solid.
4. conduct current.
A soluble ionic compound in aqueous form will be able to 4. conduct current
An aqueous ionic compound is able to conduct current because:
They possess charged ions They are able to move aroundAs a result of being able to move around in a solution, the ions of aqueous compound will be able to carry electricity from one point to another and so will be able to conduct electricity.
In conclusion, aqueous solutions of ionic compounds can conduct current.
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Answer:
4. conduct current
The reaction of sodium peroxide and water produces sodium hydroxide and oxygen gas. The following balanced chemical equation represents the reaction.
2 Na^2O^2(s) + 2 H2O(l) → 4 NaOH(s) + O^2(g)
If 15.7 moles of sodium hydroxide are produced, how many moles of O2 will be made?
Answer:
3.925 mol.
Explanation:
From the balanced equation:2 Na₂O₂(s) + 2 H₂O(l) → 4 NaOH(s) + O₂(g) ,
It is clear that 2 moles of Na₂O₂ react with 2 moles of H₂O to produce 4 moles of NaOH and 1 mole of O₂ .
Using cross multiplication:
4 moles of NaOH produced with → 1 mole of O₂ .
15.7 moles of NaOH produced with → ??? mole of O₂ .
∴ The no. of moles of O₂ made = (1 mole)(15.7 mole)/(4 mole) = 3.925 mol.
When 15.7 moles of sodium hydroxide are produced, 3.925 moles of oxygen gas will be made, using the 4:1 mole ratio between NaOH and O2 from the balanced chemical equation.
Explanation:To determine how many moles of O2 will be made when 15.7 moles of sodium hydroxide are produced, we use the stoichiometric relationship from the balanced chemical equation provided.
According to the balanced equation:
2 Na2O2(s) + 2 H2O(l) → 4 NaOH(s) + O2(g)
For every 4 moles of NaOH produced, 1 mole of O2 is produced. This suggests a 4:1 ratio between NaOH and O2.
To find the number of moles of O2 produced, we set up a ratio:
(15.7 moles NaOH) × (1 mole O2 / 4 moles NaOH) = 3.925 moles O2
Therefore, when 15.7 moles of sodium hydroxide are produced, 3.925 moles of oxygen gas are produced.
As pH increases, what happens to the hydrogen ion concentration?
a. increases
b. decreases
c. equals the pH number
Answer:
According to libretexts the answer would be B. decreases.
Explanation:
If the hydrogen concentration increases, the pH decreases, causing the solution to become more acidic. This happens when an acid is introduced. ... If the hydrogen concentration decreases, the pH increases, resulting in a solution that is less acidic and more basic
Answer:
The answer is B: it Decreases
Which element is in both graphite and diamond?
Helium
Carbon
Nitrogen
Lithium
Answer:
Carbon
.. Both graphite snd diamond are carbon containing elements
Carbon is present in both diamond and graphite.
Explanation:The allotropes of carbon are called as Graphite and diamond. These minerals synthetically comprise of carbon molecules with various physical properties. These minerals, when all in options, are referred to be as polymorphs, having a similar kind of science, however of the different crystalline structures.
In these allotropes of carbon, the molecules comprising of carbon atoms in that of the Diamond and Graphite, are bound together by solid covalent bonds with various courses of action.
Valuable stone and graphite have move structures which speak to their assorted properties, and both are unadulterated carbon. In any case, the graphite's particles join to the three atoms of carbon and get related with the plates that are parallel to one another. The particles of Diamond enter the four atoms of carbon in an outline.
Write the balanced chemical equation for the following reaction. Phases are optional. Solid calcium chlorate decomposes to form solid calcium chloride and oxygen gas.
Answer:
Ca(ClO₃)₂ (s) → CaCl₂ (s) + 3O₂ (g)Explanation:
1) Word equation (given)
calcium chlorate (solid) → solid calcium chloride (solid) + oxygen (gas)2) Chemical formulae of the reactant and products:
Calcium chlorate:The most common oxidation states of chlorine are -1, +1, +3, +5, +7.
The suffix ate in chlorate means that chlorine atom is with the third lowest oxidation state (counting only the positive states). So, this is +5.
The oxidation state of calcium is +2.
Hence, the chemical formula of calcium chlorate is Ca(ClO₃)₂
Calcium chlorideThe suffix ide in chloride means that chlorine is with oxidation state -1. Again the oxidation state of calcium is +2.
Hence, the chemical formula of calcium chloride is CaCl₂
OxygenOxygen gas is a diatomic molecule, so its chemical formula is O₂.
PhasesThe symbols s and g (in parenthesis) indicate the solid and gas phases respectively.
3) Chemical equation:
Ca(ClO₃)₂ (s) → CaCl₂ (s) + O₂ (g)That equation is not balanced becasue the number of O atoms in the reactant side and in the product side are different.
4) Balanced chemical equation:
Add a 3 as coefficient in front of O₂(g), in the product side to balance:
Ca(ClO₃)₂ (s) → CaCl₂ (s) + 3O₂ (g)Verify that all the atoms are balanced:
Atom Reactant side Product side
Ca 1 1
Cl 2 2
O 3×2 = 6 2×3 = 6
Conclusion: the equation is balanced and the final answer is:
Ca(ClO₃)₂ (s) → CaCl₂ (s) + 3O₂ (g)The decomposition of solid calcium chlorate into solid calcium chloride and oxygen gas is represented by the balanced chemical equation 2Ca(ClO3)2(s) → 2CaCl2(s) + 3O2(g).
Explanation:The balanced chemical equation for the decomposition of solid calcium chlorate to form solid calcium chloride and oxygen gas is:
2Ca(ClO3)2(s) → 2CaCl2(s) + 3O2(g)
This reaction involves the breakdown of calcium chlorate, a chlorate compound, into calcium chloride, a chloride compound, and the release of oxygen gas. This type of reaction is known as a decomposition reaction, where a single compound breaks down to form two or more simpler substances.
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Arrhenius theorized that a base is a chemical compound that
Answer:
Arrhenius theorized that a base is a chemical compound that contains hydroxide ions (OH⁻) and ionizes in water releasing them.
Explanation:
Svante Arrhenius was the first scientist to theorize about acids and bases.
Arrhenius' acid base theory states that an acid is a compound that contains hydrogen atoms and ionizes in water to produce hydrogen ions (H⁺), and a base is a compound that contains hydroxide ions (OH⁻) that are released in water.
These are some examples of compounds which can be named as acid or base following Arrhenius' theory:
HCl: is an acid because it ionizes in water producing H⁺.H₂SO₄: is an acid because it ionizes in water producing H⁺NaOH: is a base because it ionizes in water producing OH⁻Ba(OH)₂: is a base because it ionizes in water producing OH⁻This theory is limited because it does not include compounds that do not contain or ionizes producting H⁺ or OH⁻. E.g. NH₃, which is a base (according to other theory).
Arrhenius theorized that a base is a chemical compound that dissolves in water to yield hydroxide anions (OH-) or absorbs hydrogen ions (H+) in a solution, thereby reducing acidity. The strength of a base depends on how readily it releases its hydroxide ions or absorbs hydrogen ions. Stronger bases release more hydroxide ions leading to higher pH.
Explanation:According to Arrhenius's theory, a base is a chemical compound that dissolves in water to yield hydroxide anions (OH-). For example, bases like ammonia can chemically react with water and release hydroxide ions in solution. Besides, a base can also absorb hydrogen ions (H+), present in the solution, resulting in reduced acidity.
The strength of a base is measured by how readily it releases its hydroxide ions or absorbs hydrogen ions. For instance, strong bases liberate most or all of their hydroxide ions, whereas weak bases release only some hydroxide ions or absorb only a few hydrogen ions.
These bases, such as bicarbonate (HCO3-), can form water molecules by combining with the H+ ions in a solution, thereby reducing the solution's acidity and raising the pH. On the other hand, stronger bases like Sodium hydroxide tend to readily donate OH-, leading to higher pH.
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A piece of fossilized wood has a carbon-14 radioactivity that is 1/4 that of new wood. the half-life of carbon-14 is 5730 years. how old is the cloth?
Answer:
1.146 x 10⁴ year.
Explanation:
The decay of carbon-14 is a first order reaction.The rate constant of the reaction (k) in a first order reaction = ln (2)/half-life = 0.693/(5730 year) = 1.21 x 10⁻⁴ year⁻¹.The integration law of a first order reaction is:kt = ln [A₀]/[A]
k is the rate constant = 1.21 x 10⁻⁴ year⁻¹.
t is the time = ??? years.
[A₀] is the initial percentage of carbon-14 = 100.0 %.
[A] is the remaining percentage of carbon-14 = 1/4[A₀] = 25.0 %.
∵ kt = ln [Ao]/[A]
∴ (1.21 x 10⁻⁴ year⁻¹)(t) = ln (100.0%)/[25.0 %]
(1.21 x 10⁻⁴ year⁻¹)(t) = 1.386.
∴ t = 1.386/ (1.21 x 10⁻⁴ year⁻¹) = 1.146 x 10⁴ year.
The piece of fossilized wood is approximately 11,460 years old, based on its carbon-14 radioactivity being 1/4 that of new wood and using the known half-life of carbon-14 which is 5730 years.
A fossilized piece of wood has a carbon-14 radioactivity that is 1/4 that of new wood. Given that the half-life of carbon-14 is 5730 years, we can estimate the age of the fossil. For each half-life that passes, the amount of carbon-14 halves. If the wood has 1/4 the radioactivity, this means that two half-lives have passed, as (1/2)² = 1/4. Therefore, using the formula for carbon dating and the known half-life of carbon-14, we can calculate that the wood is approximately 2 times 5730 years old, which is 11,460 years old.
What would the molecule CH₄ be classified as?
Alkane
Inorganic compound
Alkene
Alkyne
Answer:
Alkane
Explanation:
Definition of Alkane "any of the series of saturated hydrocarbons including methane, ethane, propane, and higher members. (google dictionary)"
CH4 is methane.