Answer:
Mass number is defined as the number of protons plus the number of neutrons.
Explanation:
Every atom of an element have proton(s), neutron(s) and electron(s). The proton number of an element is the atomic number of that element. For an electronically neutral atom the proton number is equal to the electron numbers. The neutron and the proton contributes to the mass of every atom. The electron is more active when atoms are bonding.
Mass number of an element is the number of proton plus the number of neutron.
Atomic number of an atom is the number of proton present, so it can never be atomic number.
Isotopy talks about same element having different number of neutron but same number of protons in each atom. Example is hydrogen that exist as protium, deuterium and tritium. It cannot be isotopic number.
Ionic number talks about elements that possess a charge. The elements have been ionized.
The answer is Mass number because the sum of proton number and neutron number is equals to mass number.
Mass number is defined as the number of protons plus the number of neutrons in an atom's nucleus. Atomic number is defined as the number of protons in an atom's nucleus.
The term "mass number" is defined as the number of protons plus the number of neutrons in the nucleus of an atom. It provides the total mass of the atomic nucleus and is represented by the symbol "A."On the other hand, the term "atomic number" (also known as the "proton number") is defined as the number of protons in the nucleus of an atom.It is a fundamental property of an element and determines its identity, chemical behavior, and its position in the periodic table. The atomic number is typically denoted by the symbol "Z."To clarify further:Atomic Number (Z): Defines the unique identity of an element, as each element has a distinct number of protons in its nucleus.Mass Number (A): Represents the total number of nucleons (protons and neutrons) in the atomic nucleus. It is used to differentiate between isotopes of the same element.The terms "isotopic number," "ionic number," and "nuclear number" are not standard terminology in chemistry or physics. The key concepts used to describe atomic structure are the atomic number (Z) and the mass number (A).For more such questions on protons
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Consider the chemical reaction described by the following equation.
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
ΔH = −58 kJ
What would be the enthalpy, in kilojoules, for the reaction
2NaCl(aq) + 2H2O(l) → 2HCl(aq) + 2NaOH(aq)
ΔH = ?
Answer:
ΔH = + 116 kJ
Explanation:
The equation for the reaction is given as;
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) ΔH = - 58 kJ
If we multiply the above equation all through with (2); we have:
2 × (HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) ΔH = - 58 kJ)
2HCl(aq) + 2NaOH(aq) → 2NaCl(aq) + 2H2O(l) ΔH = - 116 kJ
If we tend to reverse the above equation; we have
2NaCl(aq) + 2H2O(l) → 2HCl(aq) + 2NaOH(aq) ΔH = + 116 kJ
∴ The reaction is said to be endothermin , as 116 kJ are absorbed.
The enthalpy change for the given reaction can be used to determine the enthalpy change for a related reaction by using the additive property.
The enthalpy change (ΔH) for a chemical reaction is a measure of the heat energy transferred during the reaction. In this case, the enthalpy change for the given reaction is -58 kJ. To find the enthalpy change for the reaction 2NaCl(aq) + 2H2O(l) → 2HCl(aq) + 2NaOH(aq), we can use the fact that the enthalpy change is additive. Since the reaction is being doubled, the enthalpy change will also be doubled. Therefore, the enthalpy change for this reaction would be -116 kJ.
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A syringe containing 1.64 mL of oxygen gas is cooled from 94.6 ∘C to 0.3 ∘C. What is the final volume Vf of oxygen gas?
Answer:
[tex]V_f=V_2=1.22\times 10^{-3} L=1.22mL[/tex]
Explanation:
Use Charles's law which states: "At constant pressure, the volume occupied by a gas sample is directly proportional to the absolute temperatures they support."
This law can be expressed mathematically as follows:
[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]
Where:
[tex]V_1=Initial\hspace{3}volume=1.64mL=1.64\times 10^{-3} L\\V_2=Final\hspace{3}volume\\T_1=Initial\hspace{3}temperature=94.6$^{\circ}$C=367.75K\\T_2=Final\hspace{3}temperature=0.3$^{\circ}$C=273.45K[/tex]
Solving for [tex]V_2[/tex]
[tex]V_2=\frac{V_1*T_2}{T_1} =\frac{(1.64\times 10^{-3} )*273.45}{367.75} =1.21946431\times 10^{-3} \approx1.22\times 10^{-3} L =1.22mL[/tex]
As long as there is some residual liquid present after equilibrium is reached, the vapor pressure of a liquid at any given temperature is an intensive property of the liquid.
Is this true or false?
Answer:
True
Explanation:
Every material in made up of intensive or extensive property. Intensive property of a system does not depend on the system size or the amount of material in the system. But extensive property on the other hand depends on the amount of material present in the system.
Examples of intensive properties include temperature, density, vapor pressure and viscosity.
Assuming that there is some residual liquid left after equilibrium is reached, no matter how much liquid is present, at any given temperature, the vapor pressure will be the same because it is an intensive property.
At 15°C, the value of Kw is 4.5 × 10⁻¹⁵. What is the equilibrium concentration of OH⁻ at this temperature?
Answer:
Explanation:
In this problem, only the Kw is given and you need to figure out what the [OH-] concentration is. The only was of going such is filling in "x" for both [H+] and [OH-] due to both parts of the equation not being listed. From here, just solve for "x".
At 15°C, the equilibrium concentration of OH⁻ ions in pure water is calculated to be approximately 6.7 × 10⁻⁸ M using the square root of the given Kw value, 4.5 x 10⁻¹⁵.
Explanation:In the given question, we are asked to calculate the equilibrium concentration of hydroxide ions, [OHˉ], at a temperature of 15°C where the autoionization constant of water (Kw) is given to be 4.5 × 10⁻¹⁵. We know that:
Kw = [H3O+][OHˉ].
In pure water at equilibrium, the concentration of H3O+ equals the concentration of OHˉ. Hence, we can rewrite the expression as:
Kw = [OHˉ]² or [OHˉ] = √Kw.
Substituting Kw with 4.5 × 10⁻¹⁵, we find:
[OHˉ] = √(4.5 × 10⁻¹⁵) = 6.7 × 10⁻⁸ M
This means, at 15°C, the equilibrium concentration of OHˉ is 6.7 × 10⁻⁸ M.
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An aqueous mixture containing starch (a colloid), Nacl, glucose, and albumin (a colloid) is placed in a dialyzing bag and in distilled water. Which of the following correctly describes the location of the indicated substance after dialysis? starch outside O water inside only O albumin, inside albumin inside and outside starch inside and outside My Answers Give Up Submit provide Eeedback Continue
An aqueous mixture containing starch (a colloid), NaCl, glucose, and albumin (a colloid) is placed in a dialyzing bag and immersed in distilled water. Which of the following correctly describes the location of the indicated substance after dialysis?
A-albumin, inside
B-starch outside
C-albumin inside and outside
D-water inside only
E-starch inside and outside
Answer: A Correct
Explanation: A dialyzing bag is a visking device i.e. artificial semi-permeable membrane tubing used for a differential molecular movement across to the medium/cell membrane (separation techniques), that allows the flow of smaller molecules (low-molecular-weight molecules) in solution on the basis of differential diffusion.
Tiny molecules like water and glucose can pass through its microscopic pores while larger molecules like salt ions of NaCl, albumin, sucrose and starch cannot pass through the pore.
So, the salt ions of NaCl, albumin, sucrose and starch stays inside the bag, only glucose can go out of the bag and water may also diffuse into the bag from outside .
After dialysis, starch will be found outside the bag, while glucose, albumin, and NaCl will be found inside the bag.
An aqueous mixture containing starch (a colloid), NaCl, glucose, and albumin (a colloid) is placed in a dialyzing bag and in distilled water. After dialysis, the starch will be found outside the bag, while the glucose, albumin, and NaCl will be found inside the bag. The starch particles are too large to pass through the semi-permeable dialyzing membrane, so they remain outside the bag, while the smaller glucose, albumin, and NaCl molecules are able to pass through the membrane and are found inside the bag.
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How much water can be raised from 25*C (room temperature) to 37*C (body temperature) by adding the 2,000 kJ in a Snickers bar?
Answer:
m = 39834.3 g
Explanation:
Given data:
Mass of water raised = ?
Initial temperature = 25°C
Final temperature = 37°C
Energy added = 2000 Kj (2000 ×1000= 2000,000 j
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = T2 - T1
ΔT = 37°C - 25°C
ΔT = 12°C
c = 4.184 g/j.°C
Q = m.c. ΔT
2000,000j = m .4.184 g/j.°C. 12°C
2000,000j = m. 50.208 g/j
m = 2000,000j / 50.208 g/j
m = 39834.3 g
Which response contains all of the following I) PCl3 + 3 H2O → 3 HCl + H3PO3 II) Fe2O3 + 3 CO → 2 Fe + 3 CO2 III) CaCO3 + 2 HNO3 → Ca(NO3)2 + CO2 + H2O that are oxidation-reduction reactions and no others?
Answer:
II) This is because Fe₂O₃ is reduced to Fe and CO is oxidized to CO₂
Explanation:
The equation II which is Fe₂O₃ + 3CO → 2Fe + 3CO₂ is the only exclusive oxidation-reduction reaction since, Fe₂O₃ is reduced to Fe by the removal of oxygen and CO is oxidized to CO₂ by the addition of oxygen.
Equation I is a hydrolysis reaction while equation III is an acid-base reaction. There is change of oxidation number in equations I and III, but they are not exclusively oxidation-reduction reactions.
The only oxidation-reduction reaction among the given reactions is option ll) Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂
To determine which among the given reactions are redox reactions, we need to check if there is a change in oxidation states of the elements involved in the reactions.
Let's analyze each reaction:
PCl₃ + 3 H₂O → 3 HCl + H₃PO₃:
Here, phosphorus (P) in PCl3 has an oxidation state of +3 and remains +3 in H3PO3. Chlorine (Cl) changes from -1 in PCl3 to -1 in HCl, and hydrogen (H) changes from +1 in H2O to +1 in HCl and H3PO3. This indicates no change in oxidation states for any element, so this is not a redox reaction.Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂:
In this reaction, iron (Fe) goes from +3 in Fe2O3 to 0 in Fe, and carbon (C) goes from +2 in CO to +4 in CO2. Since there is a change in oxidation states, it confirms that this is a redox reaction.CaCO₃ + 2 HNO₃ → Ca(NO₃)₂ + CO₂ + H₂O:
Here, calcium (Ca), carbon (C), nitrogen (N), and oxygen (O) retain their oxidation states throughout the reaction. Therefore, this is not a redox reaction.Hence, the only oxidation-reduction reaction is:
II) Fe2O3 + 3 CO → 2 Fe + 3 CO2THE LAST QUESTION I NEED, PLEASE HELP! WILL MARK BRAINLIEST IF CORRECT!
Above which point on a phase diagram can you no longer distinguish between a liquid and a gas?
melting point
triple point
critical point
boiling point
Critical Point
I took the test
While studying force fields, Ms. Garcia told her students they were about to experiment with magnets. Before beginning the magnet experiments, Ms. Garcia set up this demonstration: three magnets that seemed to hover, one above the other, without touching. Label the poles of the magnets, A, B and C, in this arrangement. A) A north, B south, C south. B) A south, B north, C north. C) A north, B north, C south. D) A, B, and C are all south poles.
Answer:
The answer is A. a north, B south and C south
Explanation:
i just took the test
Answer:
A
Explanation:
USATestprep
The double-reciprocal transformation of the Michaelis-Menten equation, also called the Lineweaver-Burk plot, is given by
1/V0= KM/(Vmax[S]) + 1/Vmax
To determine Km from a double-reciprocal plot, you would:
a. multiply the reciprocal of the x-axis intercept by –1.
b. multiply the reciprocal of the y-axis intercept by –1.
c. take the reciprocal of the x-axis intercept.
d. take the reciprocal of the y-axis intercept.
e. take the x-axis intercept, where V0= 1/2 Vmax.
Answer:
option a
Explanation:
Lineweaver–Burk plot also known as double displacement plot is used for the study of enzyme kinetics.
It is reciprocal of Michaelis-Menten equation. The Michaelis-Menten equation for enzyme catalysis is as follows:
[tex]V=\frac{V_{max} [S]}{K_m+[S]}[/tex]
Take the reciprocal
[tex]\frac{1}{V} =\frac{K_m+[S]}{V_{max}[S]} =\frac{K_m}{V_{max}} \frac{1}{[S]} +\frac{1}{V_{max}}[/tex]
The plot or graph between 1/V and 1/[S] is called Lineweaver–Burk plot.
Slope of the plot is [tex]\frac{K_m}{V_{max}}[/tex].
Intercept of y-axis is .
Intercept of x-axis is [tex]-\frac{1}{K_m}[/tex]
Therefore, by taking the reciprocal of intercept of x-axis and multiplying by -1, Km value can be determined.
Therefore, the correct option is a.
To determine Km from a Lineweaver-Burk plot, multiply the reciprocal of the x-axis intercept by -1.
Explanation:To determine the Michaelis constant (Km) from a double-reciprocal plot or Lineweaver-Burk plot, you need to focus on the x-axis intercept. According to the Lineweaver-Burk equation:
1/V0 = (Km/Vmax)(1/[S]) + (1/Vmax)
Where V0 is the initial velocity, Vmax is the maximum velocity, [S] is the substrate concentration, and Km is the Michaelis-Menten constant.
To find Km, you should take the reciprocal of the x-axis intercept and multiply it by -1. This is because the x-axis intercept represents -1/Km in the Lineweaver-Burk plot. Therefore, the correct answer is:
a. multiply the reciprocal of the x-axis intercept by -1.When calculating the wattage for a power supply by estimating its needs, how much wattage would you allow for a fan?
Answer:
A fan is a common house appliance which is attached to the ceiling and uses an electric motor to rotate blades or paddles in a circular motion. Ceiling fans help cool a room by moving air which causes evaporative cooling. Fans range in size from 36 inches to 56 inches using 55 to 100 watts, a typical 48 inch ceiling fan will use 75 watts.
where you have
Hours Used Per Day:5
Power Use (Watts): 75
Price (kWh): 0.01
then you have
Cost Per Hour=0.0075
Cost Per Day= 0.0375
Cost Per Month=1.14
Cost Per Year=13.69
kWh Per Day: 0.38
Answer:
5W
Explanation:
Magnesium reacts with a certain element to form a compound with the general formula MgX. What would the most likely formula be for the compound formed between potassium and element X?
Answer:
K2X
Explanation:
Valency can be defined as the combining power of an element. It is the valency that dictates the value an element will have when writing a chemical formula for its compound.
MgX is a compound of magnesium and an element X. The valency of magnesium in most of its compound is +2. Now for the 2 to have been absent in the chemical formula, this shows that the element X itself have a valency if -2 for the valencies of both to have canceled out.
Now considering the element potassium, it is an alkaline metal belonging to group 1 of the periodic table. Hence, it is expected that it has a valency of +1
Forming a compound with element X means there would be an exchange of valencies between the two. We have established that x has a valency of -2. The formula of the compound thus formed by exchanging the valencies of both element would be K2X
The most likely formula for the compound formed between potassium and element X would be [tex]K_2X[/tex].
Magnesium reacts with X to form MgX.
Magnesium has 2 valence electrons ([tex]Mg^2^+[/tex]), in order to form MgX with the element X, it means X must have the capacity to accept the 2 valence electrons from Mg. Thus, X would carry a deficit of 2 electrons in its valence shell ([tex]X^2^-[/tex]).
Potassium has one valence electron ([tex]K^+[/tex]). In order for [tex]X^2^-[/tex] to react with potassium, 2 atoms of potassium would be needed to donate their electrons each to [tex]X^2^-[/tex] in order for X to become stable. Thus
2[tex]K^+[/tex] + [tex]X^2^-[/tex] ---> [tex]K_2X[/tex]
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Calculate the work (kJ) done during a reaction in which the internal volume contracts from 85 L to 12 L against an outside pressure of 2.4 atm.
Answer:
The work done on the system is 17.75_KJ
Explanation:
To solve this question we need to know the required equations from the given variables, thus
Initial volume = 85L
Final volume = 12L
External pressure = 2.4 atm.
work done = - PΔV
2.4×(85-12) = 175.2L×atm
Converting from L•atm to KJ is given by
1 L•atm = 0.1013 kJ
(175.2 L•atm) * (0.1013 kJ / 1 L•atm)
= 17.75 kJ
The work done on the system is 17.75_KJ
The work done on the system is -17.75 kJ.
Work done is obtained using the relation;
w = PΔV
where;
w = work done
V = change in volume
V1 = 85 L
V2 = 12 L
P = 2.4 atm
Hence;
w = 2.4 atm(12 - 85) L = -175.2 atm L
Now;
1 L atm = 101.325 J
-175.2 atm L = -175.2 atm L × 101.325 J/1 L atm = -17.75 kJ
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For questions 22 – 24, write an equation for the reaction of hydrogen chloride and sodium sulfide to produce hydrogen sulfide with sodium chloride.
22. Show the formulas of the reactants.
23. Show the formulas of the products.
24. Write the balanced the equation for this reaction.
Answer:
1. The reactants are HCl and Na2S
2. The products are H2S and NaCl
3. The balance equation is given below:
2HCl + Na2S —> H2S + 2NaCl
Suppose that 0.48 g of water at 25∘C∘C condenses on the surface of a 55-gg block of aluminum that is initially at 25∘C∘C. If the heat released during condensation goes only toward heating the metal, what is the final temperature (in degrees Celsius) of the metal block
Final answer:
After calculating the heat released by the condensation of water and equating it to the heat absorbed by the aluminum block, the final temperature of the aluminum block is found to be approximately 25.2°C.
Explanation:
The question asks us to determine the final temperature of an aluminum block after heat transfer occurs due to condensation of water on its surface. Both the water and the aluminum block initially have the same temperature of 25°C. We can use the concept of thermal equilibrium and specific heat capacity to solve this problem.
The heat released during the condensation of water (Qwater) is used to increase the temperature of the aluminum block (Qaluminum). According to the principle of conservation of energy, Qwater = Qaluminum.
We can calculate Qwater using the latent heat of condensation for water, which is 2260 J/g. Since 0.48 g of water condenses:
Qwater = mass × latent heat = 0.48 g 2260 J/g = 1084.8 J
Next, we calculate the change in temperature of the aluminum block using its specific heat capacity (900 J/kg•K), which allows us to find the final temperature:
Qaluminum = mass × specific heat capacity × change in temperature
1084.8 J = 0.055 kg × 900 J/kg•K × (final temperature - initial temperature)
Now, isolating the final temperature, we can solve for it:
final temperature = (1084.8 J / (0.055 kg × 900 J/kg•K)) + 25°C
final temperature = 25.2°C
Thus, the final temperature of the aluminum block, after absorbing the heat from the condensation of water, is approximately 25.2°C.
Which of the following statements about noncovalent interactions are true? Charge-charge interactions (salt bridge, ionic bond) are electrostatic interactions between a pair of ions. The energies of dipolar interactions depend on the relative orientation of the dipole. Van der Waals interactions have the shortest interaction range of noncovalent interactions. Hydrogen bonds are not directional.
Answer:
Charge-charge interactions (salt bridge, ionic bond) are electrostatic interactions between a pair of ions is True.
Explanation:
Electrostatic interaction between pairs of ions involves the transfer of ion/charges from two bonding elements in their ionic state
_____ is the process of an atom giving up or gaining one or more electrons through its interactions with other atoms.
Answer: ionization
Explanation:
is the minimum amount of energy required to remove the most loosely bound electron of an isolated neutral gaseous atom or molecule
Ionic bonding is the process of an atom giving up or gaining one or more electrons through its interactions with other atoms. It involves the transfer of electrons between atoms to form ions and create an ionic bond.
Explanation:Ionic bonding is the process of an atom giving up or gaining one or more electrons through its interactions with other atoms.
During this process, atoms with fewer electrons in their outermost energy level, known as valence electrons, tend to give up those electrons and become positively charged ions. Atoms with more valence electrons tend to gain electrons and become negatively charged ions. This transfer of electrons creates an electrostatic attraction between the positive and negative ions, resulting in the formation of an ionic bond.
For example, in the compound sodium chloride (NaCl), sodium loses one electron to become a positively charged ion (Na+) and chlorine gains that electron to become a negatively charged ion (Cl-). The positively charged sodium ion and the negatively charged chloride ion are then attracted to each other, forming an ionic bond.
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In a sealed gas-liquid system at constant temperature, eventually...?
there will be no more evaporation.
the rate of evaporation equals the rate of condensation.
the rate of condensation decreases to zero.
the rate of condensation exceeds the rate of evaporation.
Explanation:
Evaporation
It is the process of converting liquid into vapors .
Condensation
It is the process of converting vapors back into liquid state .
Suppose if we have a sealed container and we are supplying it with no or little heat , we will see that as we increase heat , the particles starts moving faster .When they move they also colloide and transfer energies .The kinetic energies of certain molecule increase to an extent that they leave the other particles and escape in atmosphere .That is evaporation occurs .At the same time when these vapors collide with each other or with the walls of container they get cooled and again get converted to liquid state .It is seen that a equilibrium is reached when "rate of evaporation becomes equal to rate of condensation ".
Calculate the number of moles of each compound, given the number of molecules. If you need to make a number a superscript, put a ^ in front of the number. For example, 2.45 x 1022 would be written as 2.45 x 10^22. 2.46 x 1021 molecules of CO2 10,000 molecules of H2O 8.75 x 1032 molecules of C6H12O6
The number of moles in each compound is:
2.46 x 10²¹ molecules CO₂ = 0.00408 mol CO₂10,000 molecules H₂O = 1.66 × 10⁻²⁰ mol H₂O8.75 x 10³² molecules C₆H₁₂O₆ = 1.45 × 10⁹ mol C₆H₁₂O₆What is Avogadro's number?
It is the number of atoms or molecules in one mole of a substance, equal to 6.023 × 10²³.
We want to convert molecules to moles, so Avogadro's number will be the conversion factor.
2.46 x 10²¹ molecules CO₂ × 1 mol CO₂/6.023 × 10²³ molecules = 0.00408 mol CO₂10,000 molecules H₂O × 1 mol H₂O/6.023 × 10²³ molecules = 1.66 × 10⁻²⁰ mol H₂O8.75 x 10³² molecules C₆H₁₂O₆ × 1 mol C₆H₁₂O₆/6.023 × 10²³ molecules = 1.45 × 10⁹ mol C₆H₁₂O₆The number of moles in each compound is:
2.46 x 10²¹ molecules CO₂ = 0.00408 mol CO₂10,000 molecules H₂O = 1.66 × 10⁻²⁰ mol H₂O8.75 x 10³² molecules C₆H₁₂O₆ = 1.45 × 10⁹ mol C₆H₁₂O₆Learn more about Avogadro's number here: https://brainly.com/question/8946174
Final answer:
To find the moles for CO2, H2O, and C6H12O6, we divide the number of molecules by Avogadro's number, yielding 4.09 × 10^-3 mol for CO2, 1.66 × 10^-20 mol for H2O, and 1.45 × 10^9 mol for C6H12O6.
Explanation:
To calculate the number of moles of each compound given the number of molecules, we will use Avogadro's number (6.022 × 10^23), which represents the number of particles in one mole of a substance. The formula to convert molecules to moles is:
Number of moles = (Number of molecules) / (Avogadro's number)
For CO2 (carbon dioxide):
Number of moles = (2.46 × 10^21 molecules) / (6.022 × 10^23 molecules/mol) ≈ 4.09 × 10^-3 mol
For H2O (water):
Number of moles = (10,000 molecules) / (6.022 × 10^23 molecules/mol) ≈ 1.66 × 10^-20 mol
For C6H12O6 (glucose):
Number of moles = (8.75 × 10^32 molecules) / (6.022 × 10^23 molecules/mol) ≈ 1.45 × 10^9 mol
Determine the concentration of a solution made by dissolving 44.0 g of calcium chloride (CaCl2) in 0.30 L of solution. SHOW YOUR WORK for credit. Partial credit is awarded! Correct answers with no work will not receive credit. Reminder of the the steps: 1. Identify what you know and what you want, and the units. Known: 0.30 L, 44.0 g CaCl2 Want: molarity (mol /L ) 2. Find the amount of CaCl2 in moles. molar Mass of CaCl2 = 110.98 g/mol. Formula: Moles = grams / molar mass 3. Use dimensional analysis to set up and solve equation. Formula: M = mol solute / L solution
Answer:
[CaCl₂] = 1.32 M
Explanation:
We know the volume of solution → 0.30 L
We know the mass of solute → 44 g of CaCl₂
Let's convert the mass of solute to moles.
44 g . 1 mol / 110.98 g = 0.396 moles
Molarity (mol/L) → 0.396 mol / 0.3 L = 1.32 M
Students wanted to test which acid was most effective at preventing hornworms from feeding on tomato plants. The students sprayed salicylic acid on one group of 15 tomato plants and jasmonic acid on a second group of 15 tomato plants. then students placed one hornworm, with a mass of 30 to 35 mg on each tomato plant. The students recorded the mass of the hornworms after one week. Which of these should the students do to make their conclusion more scientifically valid?
a. they should spray each tomato plant with more than one acid
b. they should place different kinds of worms on the tomato plants
c. they should place more than one hornworm on each tomato plant
d. they should determine the average mass of the tomato plants along with the mass of the hornworms
they should place more than one hornworm on each tomato plant
Answer: Option D
They should determine the average mass of the tomato plants along with the mass of the hornworms
Explanation:
Determining the average mass of the tomato along with the mass of hornworms will tell the researcher whether the hornworms is still feeding on the tomato or not.
If the mass of the tomato is reducing, then the researcher would know that the acid is not effective in keeping the hornworms away from the tomato or otherwise.
18 g of argon occupy 750 ml at a particular temperature and pressure. How many grams of methane would occupy the same volume at the same temperature and pressure?
Answer:
7.21 grams is the mass of methane
Explanation:
We may use the Ideal Gases Equation to solve this:
P. V = n. R. T
Let's determine the moles of Ar
18 g . 1 mol/ 39.9 g = 0.451 mol
In both situations, volume, temperature and pressure are the same so the moles of methane will also be the same as Argon's.
Let's convert the moles to mass of CH4.
0.451 mol . 16g/1mol = 7.21 grams
Final answer:
To determine how many grams of methane would occupy 750 ml at the same temperature and pressure as 18 g of argon, calculate the moles of argon and equate it to the moles of methane needed. The mass of methane is found using its molar mass, resulting in 7.2 g.
Explanation:
The question asks about the mass of methane that would occupy the same volume under the same conditions as a given mass of argon. To solve this, we can use the Ideal Gas Law, which is PV = nRT, where P is the pressure, V is the volume, T is the temperature, R is the gas constant, and n is the number of moles. Since temperature and pressure are constant, and assuming ideal conditions, the volume of a gas is directly proportional to the number of moles. The molar mass of argon (Ar) is approximately 40 g/mol, and the molar mass of methane (CH4) is approximately 16 g/mol.
Given 18 g of Ar, we first find the number of moles of Ar: moles of Ar = 18 g / (40 g/mol) = 0.45 moles. Assuming the same number of moles are required for methane to occupy the same volume at the same conditions, we can calculate the mass of CH4 required: mass of CH4 = 0.45 moles * (16 g/mol) = 7.2 g.
Therefore, 7.2 g of methane would occupy 750 ml at the same temperature and pressure as 18 g of argon.
What is the empirical formula of a compound composed of 3.25% hydrogen ( H ), 19.36% carbon ( C ), and 77.39% oxygen ( O ) by mass? Insert subscripts as needed. empirical formula: HCO HCO
Final answer:
The empirical formula for this compound is CH₂O.
Explanation:
To find the empirical formula of a compound with given mass percentages, we first assume a sample size of 100 grams. This makes it easy to convert mass percent to grams directly. For the compound containing 40.0% C, 6.71% H, and 53.28% O, we would have 40.0 grams of carbon, 6.71 grams of hydrogen, and 53.28 grams of oxygen.
Next, we convert these masses to moles using the molar mass of each element (Carbon: 12.01 g/mol, Hydrogen: 1.008 g/mol, Oxygen: 16.00 g/mol).
Carbon: 40.0 g ÷ 12.01 g/mol = 3.33 moles of CHydrogen: 6.71 g ÷ 1.008 g/mol = 6.66 moles of HOxygen: 53.28 g ÷ 16.00 g/mol = 3.33 moles of OTo determine the simplest integer ratio of the elements, divide the moles of each element by the smallest number of moles calculated. In this case, all values come down to 1, which gives us the simple ratio of 1:2:1. Thus, the empirical formula is CH₂O.
What will be the kinetic energy change of the ram of a pile driver when it suddenly undergoes a 10 kJ decrease in potential energy?
Answer:
K.E. increase by 10 KJ.
Explanation:
Total mechanical energy of a system is always constant which is the sum of kinetic and potential energies of the system. So, when the ram of a pile driver when it suddenly undergoes a 10 kJ decrease in potential energy, its kinetic energy must have increase by 10 KJ. So, as to make their sum constant again.
Mechanical energy = Kinetic energy + potential energy = constant
Researchers tested a meteorite for organic molecules containing 13C and 15N, which are carbon and nitrogen atoms with one extra neutron. However, a skeptic questions whether these "heavy" carbon and nitrogen isotopes would readily bond to make organic molecules such as amino acids and nitrogenous bases. Would extra neutrons affect the bonding of heavy carbon and nitrogen atoms?
1.Yes, extra neutrons would make carbon and nitrogen more likely to bond.
2.No, because only electrons are involved in bonding.
3.No, because the number of protons remains the same.
4.Yes. Atoms with extra neutrons must also have extra electrons, which would affect bonding.
Answer:
The correct option is 2.No, because only electrons are involved in bonding.
Explanation:
The type of bond formed by carbon and nitrogen (carbon-nitrogen bond) is covalent bond
Also known as molecular bond, a covalent bond involves the sharing of pairs of electrons (known as bonding pairs or shared pairs) between the carbon and nitrogen atoms forming stable, balanced forces in attraction and repulsion as they share common electrons in their compounds.
This electron sharing covalent bond is what enables the formation of the several compounds between carbon and nitrogen for example, in an amine, nitrogen which has five electrons, has two remaining electrons that forms a lone pair whereby it can combine further with other elements.
Hence the factor that influences the bonds to make the numerous organic molecules is the available electrons which constitutes the shared electron pairs in covalent bonds while the neutrons which function is to keep the repulsive forces of positively charged protons from ripping the nucleus apart.
What is the symbol (including the atomic number, mass number, and element symbol) for the nitrogen isotope with 8 neutrons?
Answer:
¹⁵₇N
Explanation:
Nitrogen
Element Symbol - N
Atomic Number (No of protons) = 7
Neutrons = 8
Mass Number (Protons + Neutrons) = 7 + 8 = 15
The symbol for the nitrogen isotope with 8 neutrons is N-15.
Explanation:The symbol for an element represents its identity, and is composed of the element's atomic number and an elemental symbol. The atomic number represents the number of protons in the nucleus of an atom. The mass number represents the total number of protons and neutrons in the nucleus. To determine the symbol for the nitrogen isotope with 8 neutrons, we need to identify the atomic number and mass number for nitrogen. Nitrogen has an atomic number of 7, which means it has 7 protons. Since the mass number is the sum of protons and neutrons, we can subtract 8 neutrons from the mass number to find the number of protons in the isotope. Therefore, the nitrogen isotope with 8 neutrons has an atomic number of 7 and a mass number of 15. The symbol for nitrogen is N, so the symbol for the nitrogen isotope with 8 neutrons is N-15.
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Arrange the following 0.10 MM solutions in order of increasing acidity: (i) NH4NO3NH4NO3, (ii) NaNO3NaNO3, (iii) CH3COONH4CH3COONH4, (iv) NaFNaF, (v) CH3COONa
Final answer:
To arrange the solutions in order of increasing acidity, we must understand their hydrolysis reactions. The order from least acidic to most acidic is: CH3COONa, NaF, NaNO3, CH3COONH4, NH4NO3.
Explanation:
To arrange the 0.10 M solutions in order of increasing acidity, we need to consider the nature of each compound in water and the consequent effect on pH. Salt solutions can be acidic, neutral, or basic, depending on the ions they release into solution.
(i) NH4NO3: This salt forms from a weak base (NH4OH) and a strong acid (HNO3), so its solution is acidic because the NH4+ ion hydrolyzes to produce acid.
(ii) NaNO3: Na+ is from a strong base (NaOH), and NO3- is from a strong acid (HNO3), so the solution is neutral as neither ion hydrolyzes significantly.
(iii) CH3COONH4: This is a salt of a weak acid (CH3COOH) and a weak base (NH4OH), but since weak bases generally hydrolyze more compared to weak acids, this solution is slightly acidic.
(iv) NaF: This salt dissociates into Na+ (from NaOH, a strong base) and F- (from HF, a weak acid). The F- ion hydrolyzes water to form HF and OH-, making the solution basic.
(v) CH3COONa: This is a salt of a weak acid (CH3COOH) and a strong base (NaOH), so the solution is basic due to the hydrolysis of the acetate ion forming OH-.In summary, the order of increasing acidity (from least acidic to most acidic) is: CH3COONa < NaF < NaNO3 < CH3COONH4 < NH4NO3.
A BaSO4 slurry is ingested before the gastrointestinal tract is x-rayed because it is opaque to x-rays and defines the contours of the tract. Ba2+ ion is toxic, but the compound is nearly insoluble. If ΔG o at 37°C (body temperature) is 59.1 kJ/mol for the process BaSO4(s) ⇌ Ba2+(aq) + SO42−(aq) what is the [Ba2+] in the intestinal tract? (Assume that the only source of SO42− is the ingested slurry.)
Explanation:
The given reaction equation is as follows.
[tex]BaSO_{4}(s) \rightleftharpoons Ba^{2+}(aq) + SO_{4}^{2-}(aq)[/tex]
The value of [tex]\Delta G^{o}[/tex] = 59.1 kJ/mol
We know that ,
[tex]\Delta G^{o} = -RT ln K_{sp}[/tex]
or, [tex]ln K_{sp} = -(\frac{\Delta G^{o}}{RT}) [/tex]
= -(\frac{59.1 kJ/mol}{(8.314 \times 10^{-3} kJ/mol.K \times 310 K))}[/tex]
= -22.93
or, [tex]K_{sp} = e^{-22.93}[/tex]
= [tex]1.1 \times 10^{-10}[/tex]
[tex]K_{sp} = [Ba^{2+}][ SO_{4}^{2-}][/tex]
Therefore, [tex][Ba^{2+}] =\sqrt{K_{sp}}[/tex]
= [tex]\sqrt{ 1.1 \times 10^{-10}}[/tex]
= [tex]1.05 \times 10^{-5} M[/tex]
Therefore, we can conclude that the value of [tex][Ba^{2+}][/tex] in the intestinal tract is [tex]1.05 \times 10^{-5} M[/tex].
The concentration of Ba2+ (barium ions) in the intestinal tract following the ingestion of BaSO4 slurry can be calculated using the equilibrium constant (K) derived from the Gibbs free energy equation. After performing the calculations, [Ba2+] is found to be 3.45 x 10⁻⁶ M.
Explanation:The question is essentially asking for the concentration of Ba2+ ions in the intestinal tract following the ingestion of BaSO4 slurry, given a ΔG° value of 59.1 kJ/mol at 37°C. In order to solve this, we need to consider the process of the reaction: BaSO4(s) ⇌ Ba2+(aq) + SO42−(aq). From the Gibbs free energy equation, we can calculate the equilibrium constant (K) as: K = e^(-ΔG°/RT), where R is the gas constant (R = 8.314 J/molK) and T is the temperature in Kelvin (37°C = 310K).
Therefore, ΔG° = -RTlnK -> K=e^(-ΔG°/RT). We find K = e^(-(−59.1×10³J mol⁻¹)/((8.314 J K⁻¹ mol⁻¹)(310 K))), which gives K = 1.19 x 10⁻¹⁰. Since the equilibrium involves the dissolution of one BaSO4 molecule to give one Ba2+ ion and one SO42- ion, the equilibrium concentrations of Ba2+ and SO42- are equal. Hence, [Ba2+] = sqrt(K) = sqrt(1.19 x 10⁻¹⁰) = 3.45 x 10⁻⁶ M.
In conclusion, the concentration of Barium ions, Ba2+, in the intestinal tract following ingestion of BaSO4 slurry would be around 3.45 x 10⁻⁶M.
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Two hydraulic cylinders are connected. If the diameter of one piston is twice the other, the how does the pressure experienced by the smaller piston compare to the pressure experienced by the larger piston?
Answer:
They experience the same pressure
Explanation:
To answer this question, we recall Pascal's, Law Pascal's law states that an increase in pressure at a point in a confined cylinder containing a fluid, there is also an equal increase at all other points in that cylinder.
According to Pascal's law the pressure if the pressure expereienced by the larger diameter piston increases, the pressure experienced by the smaller diameter piston also increases by the same amount
However considering that pressure = Force/area F1/A1 =F2/A2
thus where A1 = πD²÷4 and A2 = πD²÷ 16 we have
we have F1×4/πD² = F2×16/πD² or F1 = 4× F2
They experience the same pressure but the larger cylinder delivers four times the force transmitted from he outside to the smaller cylinder
The current model of the atom in which essentially all of an atom's mass is contained in a very small nucleus, whereas most of an atom's volume is due to the space in which the atom's electrons move was established by OA) Millikan's oil drop experiment B) Rutherford's gold foil experiment C) Thomson's cathode ray tube experiment. D) None of these
The current model of the atom was established by Rutherford's gold foil experiment. This experiment proved that atoms are mostly empty space with a small, dense nucleus, replacing Thomson's plum pudding model.
Explanation:The current model of the atom in which essentially all of an atom's mass is contained in a very small nucleus, whereas most of an atom's volume is due to the space in which the atom's electrons move, was established by B) Rutherford's gold foil experiment. In this experiment, Rutherford observed that most of the alpha particles passed straight through the gold foil which indicated that atoms are mostly empty space with a small, dense nucleus. This model replaced the previously accepted Thomson's plum pudding model. Thus, the structure of the atom as we know it today, was primarily established through Rutherford's experiment.
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