Answer:
1) a) [OH⁻] = 0.025 M.
b) pH = 12.4.
c) The solution is basic.
2) a) [OH⁻] = 1.66 x 10⁻⁸ M.
b) pH = 6.22.
c) The solution is acidic.
3) a) [H⁺] = 3.16 x 10⁻⁴ M.
b) pH = 3.5.
c) The solution is acidic.
4) a) [H⁺] = 3.16 x 10⁻⁷ M.
b) pH = 6.5.
c) The solution is acidic.
Explanation:
1) In saturated lime water, [H⁺] = 3.98 x 10⁻¹³ M.
a) Find [OH⁻]
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/(3.98 x 10⁻¹³ M) = 0.025 M.
b) What is the pH?
∵ pH = - log[H⁺].
[H⁺] = 3.98 x 10⁻¹³ M.
∴ pH = - log(3.98 x 10⁻¹³ M) = 12.4.
c) Is the solution acidic, basic, or neutral?
We can determine the nature of the solution, acidic, basic or neutral, from the value of the pH.pH is a scale from 0 to 14.
If pH < 7, the solution is acidic.If pH = 7, the solution is neutral.If pH > 7, the solution basic.∵ pH = 12.4 > 7.
∴ The solution is basic.
2) In butter, [H⁺] = 6.0 x 10⁻⁷ M.
a) Find [OH⁻]
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/(6.0 x 10⁻⁷ M) = 1.66 x 10⁻⁸ M.
b) What is the pH?
∵ pH = - log[H⁺].
[H⁺] = 6.0 x 10⁻⁷ M.
∴ pH = - log(6.0 x 10⁻⁷ M) = 6.22.
c) Is the solution acidic, basic, or neutral?
We can determine the nature of the solution, acidic, basic or neutral, from the value of the pH.pH is a scale from 0 to 14.
If pH < 7, the solution is acidic.If pH = 7, the solution is neutral.If pH > 7, the solution basic.∵ pH = 6.22 < 7.
∴ The solution is acidic.
3) In peaches, [OH⁻] = 3.16 x 10⁻¹¹ M
a) Find [H⁺]
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [H⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(3.16 x 10⁻¹¹ M) = 3.16 x 10⁻⁴ M.
b) What is the pH?
∵ pH = - log[H⁺].
[H⁺] = 3.16 x 10⁻⁴ M.
∴ pH = - log(3.16 x 10⁻⁴ M) = 3.5.
c) Is the solution acidic, basic, or neutral?
We can determine the nature of the solution, acidic, basic or neutral, from the value of the pH.pH is a scale from 0 to 14.
If pH < 7, the solution is acidic.If pH = 7, the solution is neutral.If pH > 7, the solution basic.∵ pH = 3.5 < 7.
∴ The solution is acidic.
4) During the course of the day, human saliva varies between being acidic and basic. If [OH⁻] = 3.16 x 10⁻⁸ M,
a) Find [H⁺]
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [H⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(3.16 x 10⁻⁸ M) = 3.16 x 10⁻⁷ M.
b) What is the pH?
∵ pH = - log[H⁺].
[H⁺] = 3.16 x 10⁻⁷ M.
∴ pH = - log(3.16 x 10⁻⁷ M) = 6.5.
c) Is the solution acidic, basic, or neutral?
We can determine the nature of the solution, acidic, basic or neutral, from the value of the pH.pH is a scale from 0 to 14.
If pH < 7, the solution is acidic.If pH = 7, the solution is neutral.If pH > 7, the solution basic.∵ pH = 6.5 < 7.
∴ The solution is acidic.
The number of grams per mole of something is also known as_______
Answer:
Molar mass
Explanation:
This is a counting unit which represents the mass in grams of a substance that make up one mole of the substance. This mass is calculated as follows:
Molar mass = Mass/ Number of moles
Units: grams/mol
Molar mass is also known as number of grams/mole of something.
Explanation:A substance's molar mass is defined as substance mass divided by the substance amount in moles. It is expressed in Kg/mol but gram/mol is used for the convenience for study.
It is often used in chemistry for the conversion of mass in grams to substance moles. The relation that is used to convert the gram top mole is that the molar mass is equal to the molecular mass in grams.
4 what is the net amount of heat released when two moles of c2h6(g) are formed from its elements at 101.3 kpa and 298 k?
I know the final answer is -168 bc somehow you get -84 from somewhere i'm just not sure where that comes from.
Answer:
because reference table I shows that delta h for one mole of c2h6(g) is 84.0 kj so for 2 moles of c2h6(g) is 168.0kj
168 kJ/mol is the net amount of heat released when two moles of C₂H₆ are formed from its elements at 101.3 kpa and 298 K.
What is Enthalpy of formation ?The standard reaction enthalpy for formation of the compound from the atoms or molecules at stable states that is temperature 298 K and Pressure 1 bar is called as enthalpy of formation.
What is the enthalpy of ethane ?1 Atm (Atmospheric pressure) = 101.3 KPa (Kilopascal)
At 1 atm and 298 K the enthalpy of formation of ethane is -84 kJ/mol.
The enthalpy of formation of 1 mole of C₂H₆ is 84 kJ/mol because heat is released here so enthalpy of formation is positive.
Therefore, the enthalpy of formation of 2 mole of C₂H₆ = 2 × 84 kJ/mol
= 168 kJ/mol
Thus from the above conclusion we can say that 168 kJ/mol is the net amount of heat released when two moles of C₂H₆ are formed from its elements at 101.3 kpa and 298 K.
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How did Albert Einstein explain the photoelectric effect?
A) Light is made up of electrons
B) Light is made up of atoms
C) Light is made up of electricity
D) Light is made up of photons
Answer: D) Light is made up of photons
Light, Einstein said, is a beam of particles whose energies are related to their frequencies according to Planck's formula. When that beam is directed at a metal, the photons collide with the atoms. If a photon's frequency is sufficient to knock off an electron, the collision produces the photoelectric effect.
Option D, Light is made up of photons.
What is photoelectric effect?The photoelectric effect is a phenomenon where electrons are emitted from the metal surface when the light of sufficient frequency is incident upon. The concept of the photoelectric effect was first documented in 1887 by Heinrich Hertz and later by Lenard in 1902. But both the observations of the photoelectric effect could not be explained by Maxwell’s electromagnetic wave theory of light.
What is Einstein's photoelectric effect?Light, Einstein said, is a beam of particles whose energies are related to their frequencies according to Planck's formula. When that beam is directed at a metal, the photons collide with the atoms. If a photon's frequency is sufficient to knock off an electron, the collision produces the photoelectric effect.
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The reaction below shows a system in equilibrium.
How would a decrease in temperature affect this reaction?
A. The rate of formation of the gases would increase.
B. The equilibrium of the reaction would shift to the left.
C. The equilibrium would shift to cause the gases to sublime into solids.
D. The chemicals on the left would quickly form the chemical on the right.
The given question is incomplete, here is a complete question.
The reaction below shows a system in equilibrium.
[tex]H_2(g)+I_2(g)+Heat\rightarrow 2HI(g)[/tex]
How would a decrease in temperature affect this reaction?
A. The rate of formation of the gases would increase.
B. The equilibrium of the reaction would shift to the left.
C. The equilibrium would shift to cause the gases to sublime into solids.
D. The chemicals on the left would quickly form the chemical on the right.
Answer : The correct option is, (B) The equilibrium of the reaction would shift to the left.
Explanation :
The given reaction is endothermic reaction.
For an endothermic reaction, heat is getting absorbed during a chemical reaction and is written on the reactant side.
Any change in the equilibrium is studied on the basis of Le-Chatelier's principle. This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.
As, heat is getting absorbed during a chemical reaction. This means that temperature is getting increased on the reactant side.
If the temperature in the equilibrium is decreased, the equilibrium will shift in the direction where, temperature is getting increased. Thus, the reaction will shift in left direction that is towards the reactants.
Hence, the correct option is, (B) The equilibrium of the reaction would shift to the left.
Please help on this one?
Answer:
[tex]\text{C. } _{36}^{85}\text{Kr}[/tex]
Explanation:
Your nuclear equation is
[tex]_{35}^{85}\text{Br} \longrightarrow \, _{-1}^{0}\text{e} +\, _{x}^{y}\text{X}[/tex]
The main point to remember in balancing nuclear equations is that
the sum of the superscripts and must be the same on each side of the equation.the sum of the subscripts must be the same on each side of the equation.Then
85 = 0 + y, so y = 85 - 0 = 0
35 = -1 + x, so x = 35 + 1 = 36
The nucleus with atomic number 36 and atomic mass 85 is krypton-85.
The nuclear equation becomes
[tex]_{35}^{85}\text{Br} \longrightarrow \, _{-1}^{0}\text{e} + \, _{36}^{85}\text{Kr}[/tex]
Answer:
C
Explanation:
In an endothermic reaction, a drop in temperature would be observed.
TRUE
or
FALSE
multiple choices
Select all the correct answers.
What are some applications of fission reactions?
A)as a zero-waste energy source
B) for generating large amounts of heat
C) for creating stable elements from unstable ones
D) for creating new, heavier elements
E)as the energy source in nuclear weapons
Answer:
B, C, & E
Explanation:
Fission reaction involves the splitting of heavy unstable atoms into stable lighter atoms, with the release of energy. Fission energy is advantageous in that it produces a huge amount of energy per mass compared to other energy sources (hence also used to make nuclear bombs). However, fission produces radioactive waste particles, such as beta and alpha particles, that have high ionizing energy and can be harmful to living things.
Answer:
B and E
Explanation:
How do you find the mass number of an element
Answer:
add up the mass of protons and neutrons
Explanation:
Answer:
To find the mass number of an element you add up the number of protons (atomic number) and neutrons.Explanation:
The mass number is a specific property of the atoms, defined as the sum of the protons and neutrons, which are the subatomic particles that are in the nucleus of the atom.
The electrons do not count for the mass of atoms because their mass is about 1/1840 the mass of a proton or a neutron.
The relative masses of protons and neutrons is 1: 1, then they count equally.
As an example, the mass number of the atom carbon-12 is calculated in this way:
Atomic number of carbon: Z = 6 (6 protons)Number of neutrons: N = 6Mass number: A = Z + N = 6 + 6 = 12.The number 12 added to the name in carbon-12, stands for its mass number.
Also, the mass number is indicated as a superscript to the left of the chemical symbol of the element, and the atomic number as a subscript to the left of the chemical symbol. For the example of carbon-12 that is:
[tex]^{12}_{6}C[/tex]Describe the methods by which an electric potential develops in primary cells and dry cells.
Answer:
In a primary cell, two electrodes (one of copper and other of zinc) of metal atoms are used. These electrodes are dipped in an electrolyte solution that causes the metals to produce their respective positive and negative ions.
In this way, the flow of charges takes place and supply the electricity to the source.
Unlike a primary cell, a dry cell contains paste of an electrolyte instead of the solution. The contents of electrolyte paste react with each other through a chemical process and convert the chemical energy into electrical energy.
Answer:
In primary cells, an electric potential develops through chemical action between the plates within the cell. Positively charged ions of zinc enter the acid and free electrons released from zinc atoms collect on the zinc plate, which results in a negative charge. At the same time, positively charged ions of hydrogen from the acid remove free electrons from the copper plate, which becomes positively charged. Through a conducting material connecting the plates, free electrons move from the zinc plate to the copper plate as long as the chemical reaction lasts.
Dry cells also develop electric potential via chemical actions within the cell. Free electrons removed from the carbon rod collect on a zinc can. The rod exhibits a positive charge and the can becomes negatively charged; this allows for an electric potential to develop between these two items. Through a conducting material connecting the can to the rod, free electrons move from the can to the rod as long as the conducting path exists.
Explanation:
straight from Penn
A 100.0 mL sample of 0.300 M NaOH is mixed with a 100.0 mL sample of 0.300 M HNO3 in a coffee cup calorimeter. If both solutions were initially at 35.00°C and the temperature of the resulting solution was recorded as 37.00°C, determine the ΔH°rxn (in units of kJ/mol NaOH) for the neutralization reaction between aqueous NaOH and HCl. Assume 1) that no heat is lost to the calorimeter or the surroundings, and 2) that the density and the heat capacity of the resulting solution are the same as water. - 34.4 kJ/mol NaOH -169 kJ/mol NaOH -55.7 kJ/mol NaOH -27.9 kJ/mol NaOH -16.7 kJ/mol NaOH
Answer:
[tex]\boxed{\text{-55.8 kJ/mol NaOH}}[/tex]
Explanation:
NaOH + HNO₃ ⟶ NaNO₃ + H₂O
There are two energy flows in this reaction.
[tex]\begin{array}{cccl}\text{Heat from neutralization} & + &\text{Heat absorbed by water} & = 0\\q_{1} & + & q_{2} & =0\\n\DeltaH & + & mC\Delta T & =0\\\end{array}[/tex]
Data:
V(base) = 100.0 mL; c(base) = 0.300 mol·L⁻¹
V(acid) = 100.0 mL; c (acid) = 0.300 mol·L⁻¹
T₁ = 35.00 °C; T₂ = 37.00 °C
Calculations:
(a) q₁
[tex]n_{\text{NaOH}} = \text{0.1000 L } \times \dfrac{\text{0.300 mol}}{\text{1 L}} = \text{0.0300 mol}\\\\n_{\text{HNO}_{3}} = \text{0.1000 L } \times \dfrac{\text{0.300 mol}}{\text{1 L}} = \text{0.0300 mol}[/tex]
We have equimolar amounts of NaOH and HNO₃
n = 0.0300 mol
q₁ = 0.0300ΔH
(b) q₂
V = 100.0 mL + 100.0 mL = 200.0 mL
m = 200.0 g
ΔT = T₂ - T₁ = 37.00 °C – 35.00 °C = 2.00 °C
q₂ = 200.0 × 4.184 × 2.00 = 1674 J
(c) ΔH
0.0300ΔH + 1674 = 0
0.0300ΔH = -1674
ΔH = -1674/0.0300
ΔH = -55 800 J/mol
ΔH = -55.8 kJ/mol
[tex]\Delta_{r}H^{\circ} = \boxed{\textbf{-55.8 kJ/mol NaOH}}[/tex]
The neutralization of NaOH and HNO3 is exothermic, releasing heat which raises the temperature of the solution. The heat of the reaction can be calculated by considering the total mass of the solution and the rise in temperature, and should be divided by the moles of NaOH used to give the enthalpy change in kJ/mol.
Explanation:When aqueous NaOH is mixed with HNO3 in a coffee cup calorimeter, a neutralization reaction occurs. The equation for this reaction is NaOH (aq) + HNO3(aq) → NaNO3(aq) + H2O(l). Since it is a strongly exothermic reaction, heat is released causing the rise in observed temperature. To determine the ΔH°rxn, calculate the heat change using the equation q = ms ΔT, where m is the total mass of the solution, s is the specific heat capacity of water (4.18 J/g°C), and ΔT is the change in temperature. Convert this energy to kj, and because no heat is lost to the surroundings, the heat absorbed by the solution is the same as the heat released by the reaction. This heat of reaction is then divided by the amount of NaOH used in the reaction to give the enthalpy change in kJ/mol NaOH, which can be used to pick one of the possible answers provided.
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Classify these definitions as that of an Arrhenius acid, an Arrhenius base, or other. Arrhenius acid definition Arrhenius base definition OtherA substance that can donate a hydrogen ion to another substanceA substance that produces an excess of hydroxide ion (-OH) in aqueous solution.A substance that produces an excess of hydrogen ion (H+) in aqueous solution
Answer:
Explanation:
A substance that produces an excess of hydroxide ion (-OH) in aqueous solution.
This is an arrhenius Base
According to the arrhenius theory, a base is a substance that combines with water to produce excess hydroxide ions, OH⁻ in an aqeous solution. Examples are :
Sodium hydroxide NaOHPotassium hydroxide KOHA substance that produces an excess of hydrogen ion (H+) in aqueous solution
This is an arrhenius Acid
An arrhenius acid is a substance that reacts with water to produce excess hydrogen ions in aqueous solutions.
Examples are;
Hydrochloric acid HClHydroiodic acid HIHydrobromic acid HBrWhich element forms an ionic compound when it reacts with lithium
Answer:
Fluorine
Explanation:
Flourine forms an ionic bond when combined with lithium. The valence electronic shell of lithium has just one single electron. Fluorine has 7 electrons in its valence shell but requires just a single electron to complete its octet. When lithium and fluorine combines, fluorine achieves its octet and lithium resembles Helium, a noble gas. This transfer of electron between Li and F is what results in an ionic bond between the two elements. It is also worthy to note that for an ionic bond to form, the electronegative difference between the two atoms should be greater than 0.7.
Fluorine has an electronegativity of 4.0 and that of Li is 1.0. The difference is 3.0. This implies that an ionic compound would be formed. The compound is LiF, Lithium Fluoride.
Determine the empirical formula of the following compound if a sample contains 0.104 molK, 0.052 molC, and 0.156 molO;?
Answer:
K₂CO₃
Explanation:
Given parameters:
Number of moles of K = 0.104mol
Number of moles of C = 0.052mol
Number of moles of O = 0.156mol
Method
From the given parameters, to calculate the empirical formula of the elements K, C and O, we reduce the given moles to the simplest fraction.
Empirical formula is the simplest formula of a compound and it differs from the molecular formula which is the actual formula of a compound.
Divide the given moles through by the smallest which is C, 0.052mol. Then approximate values obtained to the nearest whole number of multiply by a factor to give a whole number ratio. This is the empirical formulaSolution
Elements K C O
Number of moles 0.104 0.052 0.156
Dividing by the
smallest 0.104/0.052 0.052/0.052 0.156/0.052
2 1 3
The empirical formula is K₂CO₃
The empirical formula of a compound containing 0.104 mol of potassium (K), 0.052 mol of carbon (C), and 0.156 mol of oxygen (O) is K2CO3, based on the smallest whole number ratio of moles of each element.
Explanation:To determine the empirical formula of a compound from the amount of moles of each element, you need to find the smallest whole number ratio of the moles of each element. For the compound mentioned with 0.104 mol K (potassium), 0.052 mol C (carbon), and 0.156 mol O (oxygen), you can do this by dividing each mole value by the smallest of the amounts of moles present.
In this case, the smallest value is 0.052 mol (carbon). So you would divide the number of moles of each element by 0.052 mol:
K: 0.104 mol / 0.052 mol = 2C: 0.052 mol / 0.052 mol = 1O: 0.156 mol / 0.052 mol = 3Therefore, the empirical formula is K2CO3.
Potassium iodide will have which molecular configuration?
Select one:
a. bent
b. linear
c. tetrahedral
d. triangular
Answer:
None of the above.
Explanation:
KI is not a molecular substance.
It is an ionic solid with the same crystal structure as NaCl.
The shapes given in the options are for molecules and three-dimensional ions.
if 58.67g of mercuric oxide were completely decomposed to generate 54.34 g of mercury how many grams of oxygen should have been produced
Answer:
4.33g
Explanation:
The reaction equation is given as:
2HgO → 2Hg + O₂
Given parameters:
Mass of HgO = 58.67g
Mass of Hg produced = 54.34g
Unknown:
Mass of oxygen produced = ?
Solution
From the reaction equation, using the mole concept, it is possible to determine the mass of oxygen gas produced.
To do this, we first determine the molar composition of the mass of the given mercury oxide. Then we use the balanced reaction equation to determine the mass of oxygen produced:
Number of moles of HgO = [tex]\frac{mass of HgO}{Molar mass of HgO}[/tex]
Molar mass of HgO = 200.6 + 16 = 216.6gmol⁻¹
Number of moles of HgO = [tex]\frac{58.67}{216.6}[/tex] = 0.271mol
From the reaction equation, we know that:
2moles of HgO produced 1 mole of O₂
0.271moles of HgO would also produce, 0.136mol
Therefore, mass of O₂ gas produced = number of moles of O₂ x molar mass
Molar mass of O₂ = 16x2 = 32gmol⁻¹
Mass of O₂ gas = 0.136 x 32 = 4.33g
interstellar clouds are primarily composed of nitrogen and oxygen. true or false?
Answer:
The statement is false
Explanation:
Interstellar clouds are not primarily composed of nitrogen and oxygen. Interstellar clouds are generally an made up of gas, plasma, and dust in our and other galaxies.
Answer: False
Explanation:
An interstellar cloud can be defined as the accumulation of gas, plasma and dust in our galaxy or other galaxy.
The composition of interstellar clouds are determined by studying the electromagnetic radiation that is received by radio waves, gamma rays on the electromagnetic spectrum.
When The electromagnetic radiations was studied then organic compounds like vinyl chloride and methanol which was not expected.
An unknown substance has been shown to have metallic bonds.
Which of the following is most likely a property of this substance?
A. low conductivity
B. low boiling point
C. high malleability
D. high solubility in water
Answer:
C.) High malleability.
Explanation:
There is a strong force between the metal ions and free floating electrons, meaning a substance with a metallic bond may be shaped and molded without breaking/fracturing due to their strength.
As the unknown substance is metal it has a characteristic property of metals which is high malleability.
What are the characteristics of metals?
An element is the simplest form of matter.Elements are further classified as metal,non -metals and metalloids. Metals possess luster and are malleable that is they can be drawn into thin sheets.They are also ductile and can be drawn into thin wires and are hard due to the strong ionic bonding present in them.
They are good conductors of heat and electricity due to the presence of mobile electrons .They have high density because of the compact arrangement of atoms .As a result of the arrangement of atoms,they have high melting points.
Malleability and ductility of metals is due to the presence of layers of atoms which can slide over each other on application of force.
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The only bonds in a formula unit of CaF2 are __________. nonpolar covalent polar covalent ionic metallic
Answer:
ionic
Explanation:
Ionic bonds exist between Ca and F ions in CaF₂. Ionic bonds are interatomic bonds formed by the transfer of electrons from one atom to the other.
The donor atom here is Ca and it has two valence electrons. Fluorine is the receiving atom with 7 electrons in its outermost shell.
Ca would give one each of its two outermost electrons to the fluorine atoms to complete their octet. Ca ion would now resemble Argon and the flourine atoms would look more like Neon atoms.
This is an ionic bond
what is the ph of 0.001 m NaOH
Answer:
11.
Explanation:
For 0.001 M NaOH:[OH⁻] = 0.001 M.
∵ pOH = - log[OH⁻]
∴ pOH = - log(0.001 M) = 3.
∵ pH + pOH = 14.
∴ pH = 14 - pOH = 14 - 3 = 11.
The pH of a 0.001 M NaOH solution is 11.00, as NaOH is a strong base that completely dissociates in water to give a hydroxide ion concentration equal to its molarity, and the pH is calculated from the hydrogen ion concentration derived from the dissociation constant of water.
The question is asking for the pH of a 0.001 M solution of NaOH, which is a strong base. In a strong base like NaOH, it dissociates completely in water, which means that the concentration of the hydroxide ions, [OH⁻], will also be 0.001 M. To find the concentration of hydrogen ions, [H+], we use the formula [H+] = 10⁻¹⁴ / [OH⁻].
Therefore, [H⁺] = 10⁻¹⁴ / 0.001 M = 1.0 x 10⁻¹¹ M. The pH is then calculated using the formula pH = -log[H+], which gives us pH = -log(1.0 x 10⁻¹¹) = 11.00.
How many moles of sodium carbonate contain 1.773 × 1017 carbon atoms?
Answer:
2.941 × 10⁻¹⁷ molExplanation:
1) Chemical formula of sodium carbonate: Na₂CO₃
2) Ratio of carbon atoms:
The number of atoms of C in the unit formula Na₂CO₃ is the subscript for the atom, which is 1 (since it is not written).Hence, the ratio is 1 C atom / 1 Na₂CO₃ unit formula.
This is, there is 1 atom of carbon per each unit formula of sodium carbonate.
3) Calculate the number of moles in 1.773 × 10⁷ carbon atoms
Divide by Avogadro's number: 6.022 × 10²³ atoms / molnumber C moles = 1.773 × 10⁷ atoms / (6.022 × 10²³ atoms/mol)number C moles = 2.941 × 10⁻¹⁷ molSince, the ratio is 1: 1, the number of moles of sodium carbonate is the same number of moles of carbon atoms.
Which of the following solutions will have the lowest freezing point?A) 0.015 m MgCl2 B) 0.0100 m NaCl C) 0.035 m CH3CH2CH2OH D) 0.0100 m Li2SO4
The solution with the lowest freezing point would likely be the 0.015 m MgCl2 solution. This is due to the principle of freezing point depression, where a solution with more solute particles will generally have a lower freezing point than a solution with fewer solute particles.
Explanation:The question asks which of the given solutions will have the lowest freezing point. This is a question related to chemistry, specifically colligative properties, one of which is freezing point depression.
In a process known as freezing point depression, solutions typically freeze at lower temperatures than pure liquids. This is because the presence of solute particles disrupts the ability of the solvent to form a regular pattern in the solid state, thus requiring a lower temperature to freeze.
To determine which solution has the lowest freezing point, we must consider both the molality of the solution and the number of solute particles produced by each formula unit of solute. Those that yield more particles upon dissociation have a greater effect on freezing point depression. In this case, 0.015 m MgCl2 should have the lowest freezing point as MgCl2 dissociates into three ions (Mg2+ and two Cl- ions), thus producing more solute particles per formula unit compared to the other given solutions.
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The solution with the lowest freezing point is A) 0.015 m MgCl₂, because it results in the highest effective particle concentration due to its dissociation into three ions in solution.
To determine this, we need to use the concept that the freezing point decreases as the concentration of dissolved particles increases. This is calculated using the van 't Hoff factor (i), which indicates the number of particles a compound dissociates into in solution.
MgCl₂ dissociates into 3 ions (1 Mg²⁺ and 2 Cl⁻), so its van 't Hoff factor is 3.
NaCl dissociates into 2 ions (1 Na⁺ and 1 Cl⁻), so its van 't Hoff factor is 2.
CH₃CH₂CH₂OH (propanol) does not dissociate in solution, so its van 't Hoff factor is 1.
Li₂SO₄ dissociates into 3 ions (2 Li⁺ and 1 SO₄²⁻), so its van 't Hoff factor is 3.
We then multiply the molality by the van 't Hoff factor to find the effective particle concentration for each solution:
A) 0.015 m MgCl₂: 0.015 m x 3 = 0.045 m
B) 0.0100 m NaCl: 0.0100 m x 2 = 0.020 m
C) 0.035 m CH₃CH₂CH₂OH: 0.035 m x 1 = 0.035 m
D) 0.0100 m Li₂SO₄: 0.0100 m x 3 = 0.030 m
The lowest freezing point corresponds to the highest effective particle concentration. Therefore, Solution A) 0.015 m MgCl2 has the lowest freezing point.
Seawater contains approximately 3.5%NaCl by mass and has a density of 1.02 g/mL. What volume of seawater contains 7.5 g of sodium ?
To find the volume of seawater containing 7.5 g of sodium, one must first convert this mass to the equivalent mass of NaCl, then calculate the total mass of seawater needed, and finally use the density of seawater to find the corresponding volume.
Explanation:The question asks to calculate the volume of seawater that contains 7.5 g of sodium. First, we need to determine the mass of NaCl which corresponds to 7.5 g of sodium. Given that the atomic weight of sodium (Na) is approximately 23 g/mol, we can find the amount of NaCl using the ratio of the molecular weight of NaCl (58.44 g/mol) to that of Na. Once we have this mass, we can use the percentage of NaCl in seawater (3.5%) to find the total mass of seawater needed. Finally, given the density of seawater (1.02 g/mL), we can calculate the volume of seawater containing this total mass.
Final answer:
To calculate the volume of seawater that contains 7.5g of sodium, we use the concentration of NaCl in seawater and the atomic masses of Na and Cl. We find that approximately 529.00mL of seawater is needed to provide 7.5g of sodium.
Explanation:
To determine the volume of seawater containing 7.5 g of sodium, we must first understand the concentration of NaCl in seawater and the atomic mass of sodium. Seawater contains approximately 3.5% NaCl by mass. Given that the atomic masses of Na and Cl are 23.0 and 35.4 respectively, we can calculate the mass of sodium in seawater. Using the percentage by mass and the given density of seawater, we can then calculate the volume.
The mass percentage of NaCl in seawater is 3.5%, which means in 100g of seawater, there is 3.5g of NaCl. To find the mass of sodium only, we consider the molar mass ratio of Na to NaCl, which is 23.0 / (23.0 + 35.4). Therefore, the mass of sodium in 3.5g of NaCl is given by:
(23.0 / 58.4) × 3.5g.
To find the mass of Na in 100g of seawater, we multiply this by the mass percentage of NaCl in seawater:
(23.0 / 58.4) × 3.5g × 1.00 = 1.39g (rounded to two decimal places).
Thus, to find the amount of seawater containing 7.5g of Na, we would do the following calculation:
(100g seawater / 1.39g Na) × 7.5g Na= 539.57g of seawater.
Finally, to convert this mass to volume using the density of seawater (1.02g/mL), the volume is:
539.57g / 1.02g/mL = 529.00mL (rounded to two decimal places).
Therefore, approximately 529.00mL of seawater contains 7.5g of sodium.
Elements in group 2 are all called alkaline earth metals. What is most similar about the alkaline earth metals?
Answer:
A main similitary all the elments have in that group is they all have 2 valance electrons
Explanation:
Explanation:
As it is known that elements present in group 2 are also known as alkaline earth metals.
Elements that belong to this group are beryllium, magnesium, calcium, strontium, barium, and radium.
Since, all of them are placed in group 2 this means that all these elements have 2 valence electrons.
Hence, all these elements will also have similar chemical properties.
How long do balloons stay inflated with helium
Answer:
Balloons last between 12-21 hours filled with helium
Explanation:
latex balloons generally last between 12-20 hours filled with helium, and about 2-3 days when treated with Hi-Float
Balloons filled with helium deflate faster than balloons filled with heavier gases due to the effusion rate of helium.
Balloons filled with helium will stay inflated for a shorter time compared to balloons filled with heavier gases like air due to the greater effusion rate of helium.
Helium-filled balloons lose their buoyancy quicker because helium effuses much more rapidly through the microscopic pores in the rubber balloon.
2) All forms of radioisotopes:
a) are radioactive, dangerous and should be banned
b) emit radiation
c) can be used medically, agriculturally and/or for electrical power
d) cause immediate health problems
Answer:
It will Cause IMMEDIATE health problems
Explanation:
Vinegar is an aqueous solution of acetic acid (HCH3COO). When vinegar reacts with dry baking soda (NaHCO3), the result is an aqueous solution of sodium acetate (NaCH3COO), liquid water, and carbon-dioxide gas, which bubbles out of the solution. Which chemical equation correctly represents this reaction?
Answer:
its a
Explanation:
The chemical equation that represents the reaction between vinegar (acetic acid) and baking soda (sodium bicarbonate) is:
[tex]\rm CH_3COOH(aq) + NaHCO_3(s) \rightarrow NaCH_3COO(aq) + H_2O(l) + CO_2(g)[/tex]
A chemical equation is a symbolic representation of a chemical reaction in the form of reactants and products.
The balanced equation for the reaction between vinegar and baking soda is represented as:
[tex]\rm CH_3COOH(aq) + NaHCO_3(s) \rightarrow NaCH_3COO(aq) + H_2O(l) + CO_2(g)[/tex]
This equation shows that acetic acid ([tex]\rm CH_3COOH[/tex]) reacts with sodium bicarbonate ([tex]\rm NaHCO_3[/tex]) to produce sodium acetate ([tex]\rm NaCH_3COO[/tex]), liquid water ([tex]\rm H_2O[/tex]), and carbon dioxide gas ([tex]\rm CO_2[/tex]).
Therefore, the above equation represents the complete balanced chemical equation for the reaction between vinegar (acetic acid) and baking soda (sodium bicarbonate).
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Which terms could have a greatest common factor of 5m2n2? Check all that apply.m5n55m4n310m4n15m2n224m3n4
Answer:
The second and the third terms from the choices:
5m⁴n³, and10m⁴n¹⁵Explanation:
The greatest common factor of a set of numbers is found by:
1) Write each number as a product of prime factors, each factor raised to the corresponding exponent (power);
2) Choose only the common prime factors, with the least exponent.
Example: find the greatest common factor of 35x²y³ and 15xy²
Prime factorization: 35x²y³ = 5¹ . 7¹ . x² . y³15xy² = 3¹ . 5¹ . x¹ . y²
Common factors (each raised to its least exponent): 5¹, x¹, and y²Greatest common factor (make the product): 5 . x . y² = 5xy²Now apply the process to the given terms:
m⁵n⁵ : these are prime factors5m⁴n³: these are prime factors10m⁴n¹⁵: prime factors = 2 . 5 . m⁴ n¹⁵.
m²n²: these are prime factors24m³n⁴: prime factors = 2³ . 3 . m³ n⁴The terms that could have a greatest common factor of 5m²n², are those that include 5m²n², and those are:
5m⁴n³, and2 . 5 . m⁴ n¹⁵ = 10m⁴n¹⁵These are the second and the third terms from the choices.
Answer:
5m⁴n³, and
10m⁴n¹⁵
Explanation:
The process n01 → p11 + β−10 n 0 1 → p 1 1 + β - 1 0 represents a(n) _____.
alpha decay
beta decay
electron capture
fusion
Answer:
beta decayExplanation:
The process is represented by the nuclear equation:
[tex]^1_0n[/tex] → [tex]^1_1p+^0_{-1}\beta[/tex]Where:
n represents a neutron,p represents a proton, andβ represents an electron.The superscripts to the leff of each symbol is the mass number (number of protons and neutrons), and the subscript to the left means the atomic number (number of protons).
Then, in this process a neutron is being transformed into a proton by the emssion of an electron (from inside the nucleus of the atom).
This electron is named beta (β) particle, and the process is called beta decay, because the neutron is changing into other subatomic particles.
Which proportionality applies to avogadro’s law?
Answer:
The volume of the gas is directly proportional and amount (moles) of the gas at constant T and P.
Explanation:
Avogadro's law states that, "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules."For a given mass of an ideal gas, the volume of the gas is directly proportional and amount (moles) of the gas at constant T and P.V ∝ n.
Which is the electron configuration for bromine? 1s22s22p63s23p64s23d104p5 1s22s22p63s23p64s23d104p6 1s22s22p63s23p44s23d104p5 1s22s22p63s23p64s23d94p5
Answer : The correct option is, [tex]1s^22s^22p^63s^23p^64s^23d^{10}4p^5[/tex]
Explanation :
The given element bromine belongs to the group 17 and period 4. The symbol of bromine is, Br.
The atomic number of bromine = 35
The total number of electrons present in bromine element = 35
Electronic configuration : It is defined as the arrangement of electrons around the nucleus of an atom.
Hence, the correct electronic configuration of bromine is,
[tex]1s^22s^22p^63s^23p^64s^23d^{10}4p^5[/tex]
I believe the correct answer choice is A