Gen Chem 2 Midterm

gas

Identify the state of matter that is the most compressible.

3

In DNA, cytosine and guanine hydrogen bond to each other with ________ hydrogen bonds.

CH₃CH₂CH₃

Identify the compound with the lowest boiling point.

Ice is less dense than water.

Explain why ice floats in water.

critical temperature

Give the term for the temperature at which the gas and liquid phases form a supercritical fluid.

11.46

The enthalpy change for converting 1.00 mol of ice at -25.0°C to water at 60.0°C is ______ kj. The specific heats of ice, water, and steam are 2.09 J/gK, and 1.84 J/gK, respectively.

5.53 kJ

Calculate the total quantity of heat required to convert 25.0 g of liquid CCl₄(l) from 45.0°C to gaseous CCl₄ at 76.8°C (the normal boiling point for CCl₄).

350 kJ

How much heat is released when 115 g of steam at 100.0°C is cooled to ice at -15.0°C? The enthalpy of vaporization of water is 40.67 kJ/mol, the enthalpy of fusion for water is 6.01 kJ/mol, the molar heat capacity of liquid water is 75.4 J/(mol ∙ °C), and the molar heat capacity of ice is 36.4 J/(mol ∙ °C).

fusion, followed by vaporization

Consider the phase diagram below. If the dashed line at 1 atm of pressure is followed from 90 to 450°C, what phase changes will occur (in order of increasing temperature)?

4.95 kJ

Ethanol (C₂H₅OH) melts at -114°C. The enthalpy of fusion is 5.02 kJ/mol. The specific heats of solid and liquid ethanol are 0.97 J/gK and 2.3 J/gK, respectively. How much heat (kJ) is needed to convert 25.0 g of solid ethanol at -125°C to liquid ethanol at -80°C?

edge length = 2√2r, 74% packing efficiency

Identify the characteristics of a face-centered cubic cell.

graphite.

An allotrope of carbon that consists of flat sheets of carbon atoms covalently bonded together as interconnected hexagonal rings is called

Which of the following represent the addition polymer formed from the compound below?

CH₂=CHCl

polyurethane

Identify the condensation polymer.

edge length = 4r/√3, 68% packing efficiency

Identify the characteristics of a body-centered cubic cell.

6

How many O^2- ions are around each Mg²⁺ ion in MgO, which has a cubic unit cell with O^2- ions on each corner and each face?

Cu SO₄

Which of the following forms an ionic solid?

4 Mg²⁺ ions and 4 O^2- ions

MgO crystallizes in a cubic unit cell with O^2- ions on each corner and each face. How many Mg²⁺ and O^2- ions are in each unit cell of MgO?

MgO

Which of the following substances should have the highest melting point?

495 pm

What is the edge length of a face-centered cubic unit cell made up of atoms having a radius of 175 pm?

Carbon dioxide

________ is the gas dissolved in carbonated drinks.

molality

Give the term for the amount of solute in moles per kilogram of solvent.

molarity

Give the term for the amount of solute in moles per liter of solution.

miscible

If two substances are soluble in all proportions then they are ________ in each other.

ethylene glycol (HOCH₂CH₂OH)

Which of the following compounds will be most soluble in ethanol (CH₃CH₂OH)?

0.500 M

Calculate the molarity of a solution that contains 0.300 moles of LiF in 0.600 L of water.

10⁹

Parts per billion requires a multiplication factor of ________.

18.1 g

What mass of SrBr₂ is contained in 80.85 g of a 22.4% by mass solution of SrBr₂ in water?

6.07 × 10^-2 mol NaI

How many moles of NaI are contained in 3470 g of water in a 0.0175 m NaI solution?

5.2 ppm

A 1.00 L sample of water contains 0.0052 g of OCH₃⁻ ions. Determine the concentration of OCH₃⁻ ions in ppm if the density of the solution is 1.00 g/mL.

ln[reactant] vs. time

What data should be plotted to show that experimental concentration data fits a first-order reaction?

the slowest step

Identify the rate-determining step.

The rate of the reaction is not proportional to the concentration of the reactant.

Give the characteristic of a zero-order reaction having only one reactant.

diffusion.

In the hydrogenation of double bonds, a catalyst is needed. In the second step, the reactants diffuse on the surface until they approach each other. This step is known as

The rate of the reaction is directly proportional to the concentration of the reactant.

Give the characteristic of a first-order reaction having only one reactant.

1/ M³ x s

What are the units of k in the following rate law?

Rate = k[X]²[Y]²

Rate = 5.2 × 10⁻³ s^-1[N₂O₅]

Determine the rate law and the value of k for the following reaction using the data provided.

2 N₂O₅(g) → 4 NO₂(g) + O₂(g) [N₂O₅]_i (M) Initial Rate (M^-1s^-1)
0.123 6.40 × 10^-4
0.174 9.05 × 10^-4
0.224 1.16 × 10^-3

2

How many half-lives are required for the concentration of reactant to decrease to 25% of its original value?

4.5 × 10³ yr

Carbon-14, which is present in all living tissue, radioactively decays via a first-order process. A one-gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per minute. If the half-life for carbon-14 is 5720 years, how old is a wood sample that gives a rate for carbon-14 decay of 7.9 counts per minute?

1/ Ms

What are the units of k in a second-order reaction?

independent of the concentration of [A]

0 order

directly proportional to the concentration of [A]

1st order

rate increased as the spuare of [A]

2nd order

the sum of all order with respect to each reactant

overall order

solubility

freezing point

melting point

density

Which of the following are characteristic properties?

moles of solute per liter of solution

Molarity

number of moles of solute per kilogram of solvent

Molality

gas

Bubbles are produced in a reaction when a _______ is created as a product.

temperature, pH, enzyme concentration, substrate concentration

What environmental factors will affect an enzyme's ability to catalyze a reaction?

increase

Does salt solubility increase or decrease as temperature increases?

true

Rate of chemical reaction is measured by the change in concentration per unit of time.

can be observed or measured without changing the identity of a sub

Match the characteristic property with its definition. Physical

change a chemical’s identity

Match the characteristic property with its definition. Chemical

100 mL of solvent

What unit is solubility measured in?

grams of solute ?

partial dissociation

Match the van't Hoff factor with its dissociation relationship. 1

total dissociation

Match the van't Hoff factor with its dissociation relationship. 2

rate law

What is this an example of?

 

rate = k [I^-]^1.5 {S₂O₈]

true

Sample size does not change the melting or boiling of a substance.

elevation

Impurities will cause a(n) ___________ in the boiling point.

water

What is considered the universal solvent?

15,000

Calculate the freezing point depression constant given the following values:

m= 0.001 kg

change in temperature= 15 degrees Celsius

(Hint: The units will be degrees Celsius/mol^-1 kg.)

acidic , alkaline

H+ and OH-

false

Denaturation is a term that refers to an enzyme releasing the products of a reaction and returns to its original shape.

False

If a substrate encounters an active site of an enzyme, the substrate has to change shape to fit the enzyme.

protein

Most enzymes are what type of biological material?

the phase transition from solid to liquid

Define fusion.

Vapor pressure increases with temperature.

Which of the following statements is TRUE?

solid

Which one of the following has a definite shape and volume?

hydrogen bonding

The two strands in DNA are held together by

7.31

The enthalpy change for converting 10.0 g of ice at -50.0°C to water at 70.0°C is ________ kJ. The specific heats of ice, water, and steam are

The solid phase of this substance is higher in density than the liquid phase.

Consider the phase diagram shown. Choose the statement below that is TRUE.

A = gas, B = solid, C = liquid, D = triple point

Assign the appropriate labels to the phase diagram shown below.

carbon

Identify the element with the largest band gap.

edge length = 2r, 52% packing efficiency

Identify the characteristics of a simple cubic cell.

weak dispersion forces

Identify the type of interaction between atoms in a nonbonding atomic solid.

silver iodide

Identify the compound that has the zinc blende structure.

128 ptm

Copper has a face-centered cubic structure and has a density of 8.96 g/cm³. What is its atomic radius?

517 pm

Barium has a radius of 224 pm and crystallizes in a body-centered cubic structure. What is the edge length of the unit cell?

354 pm

Nickel crystallizes in a face-centered cubic structure. What is the edge length of the unit cell if the atomic radius of nickel is 125 pm?

hyposmotic.

Solutions having osmotic pressures less than those of body fluids are called

The solution is considered saturated.

A solution is formed at room temperature by vigorously dissolving enough of the solid solute so that some solid remains at the bottom of the solution. Which statement below is TRUE?

a mixture in which a dispersed substance is finely divided in a dispersing medium

Define colloid.

0.0628 mol/L

The Henry's Law constant of methyl bromide, CH₃Br, is k = 0.159 mol/(L ∙ atm) at 25°C. What is the solubility of methyl bromide in water at 25°C and at a partial pressure of 300. mm Hg?

0.36 atm

Determine the partial pressure of oxygen necessary to form an aqueous solution that is 4.7 × 10^-4 M O₂ at 25°C. The Henry's law constant for oxygen in water at 25°C is 1.3 × 10^-3 M/atm.

1.00 kg of solvent.

To make a 0.125 m solution, one could take 0.125 moles of solute and add

0.20 M

Determine the solubility of CO₂ in soda water at 25°C if the pressure of CO₂ is 6.0 atm. The Henry's law constant for carbon dioxide in water at this temperature is 3.4 × 10^-2 M/atm.

10.1 g

A solution is 2.25% by weight CsF . How many grams of CsF are in 450.0 g of solution?

desorption.

In the hydrogenation of double bonds, a catalyst is needed. In the last step, the reactants must escape from the surface into the gas phase. This step is known as

Rate constants are temperature dependent.

Which of the following statements is TRUE?

2 N₂O₅ → 4 NO₂ + O₂

Write a balanced reaction for which the following rate relationships are true.

Rate = - ½ N2O5/ = ¼ NO2 = O2

1/[reactant] vs. time

What data should be plotted to show that experimental concentration data fits a second-order reaction?

8.88 × 10^-2 M/s

Given the following balanced equation, determine the rate of reaction with respect to [Cl₂]. If the rate of Cl₂ loss is 4.44 × 10^-2 M/s, what is the rate of formation of NOCl?

2 NO(g) + Cl₂(g) → 2 NOCl(g)

0.240 mol/min

The decomposition of dinitrogen pentoxide is described by the following chemical equation

2 N₂O₅(g) → 4 NO₂(g) + O₂(g)

If the rate of appearance of NO₂ is equal to 0.960 mol/min at a particular moment, what is the rate of appearance of O₂ at that moment?

2nd order

What is the overall order of the following reaction, given the rate law?

X + 2Y → 4Z Rate = k[X][Y]

depression

Impurities will cause a(n) ___________ in the melting point.

protein

Most enzymes are what type of biological material?

Polarity, pressure, molecular size, physical state of solute, surface area, and temp

Select all that will influence the solubility of a substance.

solute

substance being dissolved

solvent

substance doing the dissolving

solution

mixture of solvent and solute