Chemistry Final

How many grams of ethanol (MM = 46.08 g/mol) do you need to weigh in order to prepare 500. mL of a 0.15 M solution of ethanol in water?

3.5 grams

How many grams of sucrose, molar mass 342.34 g/mol, are dissolved in water to make 500. mL of a 0.185 M solution?

31.6 grams

The atomic number of carbon is 6. How many valence electrons does each carbon atom have?

4

The atomic number of silicon is 14. How many valence electrons does a silicon atom have?

4

Which of these is an extensive property of a wax candle?

Amount of heat produced by burning the entire candle

Which of these elements is correctly matched up with its number of valence electrons?

Bromine-7

Which chemical equation below correctly shows the conservation of matter?

C5H12 + 8O2 → 5CO2 + 6H2O

Which of the following has a Lewis structures with a double bond?

Carbon Dioxide

Which of the following is an intensive property?

Density

Which change occurs during an endothermic chemical reaction?

Energy is absorbed

Which of the following is a balanced chemical equation?

Fe2O3 + 6 HCl --> 2 FeCl3 + 3 H2O

Which of the these describe a chemical property of a substance?

Flammability of gasoline

At the molecular level, what can occur during a chemical change but not during a physical change?

Formation of covalent bonds

What are the oxidation numbers for the hydrogen and oxygen in H3O+ in the following equation? 2H3O+ + Zn --> H2 + 2H2O + Zn+2

H = +1; O = -2

Which of the following is an example of a chemical change?

Hydrogen and nitrogen form ammonia

Which of the following statements correctly describes the effect of concentration on reaction rate?

Increasing the concentration of reactants increases the reaction rate.

How is the temperature of an ideal gas related to its volume at constant pressure?

Inversely Proportional

What is the chemical formula for potassium sulfide?

K2S

Exothermic reactions result in the release of energy. Which of the following does NOT describe an exothermic reaction?

Melting of ice

What is the source of energy emitted by the Sun?

Nuclear fusion

What is the formula for the compound dinitrogen pentoxide?

N2O5

How does an increase in kinetic energy affect the motion of particles of matter?

Particles move faster as kinetic energy is added

Which is a solid that forms in a solution during a chemical reaction?

Precipitate

Which of the following particles has a positive electrical charge?

Proton

Which particles of an atom are affected by electrical forces?

Protons and electrons only

How can the following equation be balanced? (NH4)2Cr2O7 --> Cr2O3 + N2 + H2O

Put a coefficient of 4 in front of water

Which process would cause a material to change its state from gas to liquid?

Removing energy from the molecules

What are the products of the decomposition of sulfuric acid when it is heated? H2SO4 -->

SO3 + H2O

Which of the following is NOT an example of a chemical change?

Separating a solution of salt-water

Which of the following should be classified as an element?

Silver

Metals are malleable and ductile. What do these properties indicate about the bonds that hold metal atoms together?

The bonding is the same in all directions throughout the metal.

Which statement is true of Bohr's model of the atom?

The electrons travel in definite paths around a small, positively charged nucleus

During an experiment, Monique observed that an oil was not soluble in water. Which of the following is a valid conclusion?

The oil is a nonpolar covalent compound because it does not dissolve in water.

Which of the following is ALWAYS TRUE of two objects that have

The particles that make up the hotter object are moving faster.

How can you determine whether nitrogen dioxide is a compound or a mixture?

The properties of nitrogen dioxide are different from nitrogen and oxygen, so it is a compound.

A scientist carries out a reaction in a test tube. After the bubbling stops, she notices the test tube is very warm. What might she conclude about the reaction?

The reaction was exothermic

What keeps the protons in an atomic nucleus from flying away from one another?

The strong nuclear force overcomes the repulsive force of protons

Why did Thomson's results require a revision of Dalton's atomic theory?

Thomson showed that atoms are not the smallest particles of matter

What occurs during an elastic collision between gas particles?

Total kinetic energy remains the same

Which of these substances is a liquid at room temperature?

Water

The change of state from a liquid to a solid is exothermic. How could this be demonstrated in a lab?

by observing the temperature changes in the surroundings as ice forms

What type of reaction does the equation below describe? 2C4H10 + 13O2 --> 8O2 + 10H2O

combustion

When an electric current passes through water the water can react to form hydrogen and oxygen gases. What type of chemical reaction has occurred?

decomposition

When iron(III) oxide reacts with hydrogen chloride, iron(III) chloride and water are produced. What type of reaction is this?

double replacement

What force is responsible for the stability of all crystals?

electrical attraction

When sodium and chlorine react to form sodium chloride, which one of the following steps involves a release of energy?

formation of a crystal from sodium ions and chlorine ions

Which of the following states is included in an equilibrium expression?

gas aqueous

How could you speed up a chemical reaction?

increase the surface area of the reactants

Potassium iodide has a very high boiling point. What holds the particles of potassium iodide together?

ionic bonds

Which is the measure of the average kinetic energy of particles in an object?

temperature

Which elements often share properties?

those in a group

What is the charge of the nickel ion in nickel nitrate, Ni(NO3)3?

+3

A saturated solution of oxygen in water contains 0.30 grams of oxygen in each liter. What is the molarity of the solution?

.00094 M

How much of a 10.0 gram sample of a radioisotope will remain unchanged after 5 half-lives?

.3125 g

What is the oxidation number for Ca(s)?

0

What are the oxidation numbers of bromine atoms before and after the following reaction? H2 + Br2 --> 2HBr

0 and -1

A 2.80 g piece of metal absorbs 14.0 J of energy as it is heated from 22 to 35 degrees Celsius. Find the specific heat of this metal?

0.385 J/gK

A student weighs 5.0 gram of sodium fluoride, molar mass 42.00 g/mol, and dissolves it in enough water to fill a 250. mL flask. What is the concentration of the solution?

0.48 M

The atomic mass of bromine is 79.904 amu. If a chemist finds that the mass of a sample of bromine gas is 79.90 grams, how many moles of bromine gas are present?

0.5000 mol

What is the density of a cubic block of wood that measures 2.00 centimeters on each side and has a mass of 7.2 grams?

0.90 g/cm3

Mercury(II) oxide can be decomposed to form mercury and oxygen gas. What volume, in liters at STP, is occupied by the gas produced by the decomposition of 0.136 mol of HgO?

1.52L

Molybdenum has a molar mass of 95.94 g/mol. How many moles of molybdenum are present in 150.0 grams of molybdenum?

1.536 mol

A balloon has a volume of 1.5 L at 101 kPa. If the temperature remains constant, what will its volume be at 80.0 kPa?

1.9L

An atom has 5 protons, 5 neutrons and 5 electrons. What is its mass number?

10

What is the percentage by mass of hydrogen in water?

11.1%

How much of a potassium fluoride (MM = 58.10 g/mol) do you need to prepare 100. mL of a 2.00 M KF solution?

11.6 grams

The mass of a mole of sulfur atoms is 32 grams. In a chemical reaction, 2.0 moles of sulfur produces sulfur dioxide gas. What is the mass of the gas produced?

130 grams

The mass of a mole of sulfur atoms is 32.06 grams. In a chemical reaction, 2.0 moles of sulfur produces sulfur dioxide when it reacts with oxygen. What is the mass of the gas produced?

130 grams

An aerosol can contains a gas at 150 kPa. What will the pressure be if the can is heated from 20 to 85 degrees Celsius?

183kPa

Argon is the third period noble gas. What is the electron configuration of argon?

1s22s22p63s23p6

Which of the following equations is NOT balanced?

2 ZnS + 3O2 --> 2 ZnO + SO2

A student measures the volume and mass of an unknown substance in a chemistry lab. The volume is found to be 45.0 mL and the mass was measured to be 97 grams. What is the density of the substance?

2.16 g/mL

Calcium carbonate can be heated to produce calcium oxide, an industrial chemical with a wide variety of uses. The balanced chemical equation for the reaction is: CaCO3(s) --> CaO(s) + CO2(g) How much calcium carbonate must be decomposed to produce 5.00 L of carbon dioxide at STP?

22.3 g

Magnesium has three naturally occurring isotopes: Mg-24 (78.9%), Mg-25 (10.0%), Mg-26 (11.0%). What is the average atomic mass of magnesium?

24.30

Predict the product(s) of the synthesis reaction: 4Al + 3O2 -->

2Al2O3

In finding the average atomic mass of helium, scientists include only two of the element's 6 isotopes, helium-3 and helium-4, in their calculations. The four other isotopes do not naturally occur on earth. The atomic abundance of helium-4 is 0.9999986 and its mass is 4.003 amu. The atomic abundance for helium-3 is 0.0000014 and its mass is 3.016 amu. According to the given information, what is the average atomic mass for helium?

4.002994396 amu

What is the total number of ions produced by dissolving 1.0 mole of aluminum sulfate in water?

5.0 mol

You have a solution of hydrochloric acid labeled "2.00 M HCl". How much of this solution would you measure into a 250 mL flask in order to prepare a solution of HCl at a concentration of 0.40 M?

50. mL

Sodium reacts with chlorine to form sodium chloride according to the following reaction: 2Na + Cl2 --> 2NaCl How many moles of Cl2 react with 100. moles of sodium to form sodium chloride?

50.0 mol

Sodium reacts with chlorine to form sodium chloride. How many moles of chlorine react with 100. moles of sodium to form sodium chloride?

50.0 mol

Using the following balanced equation: 2H2 + O2 --> 2H2O, what is the number of moles of water that can be produced from 12 grams of hydrogen gas?

6.0 mol

How many moles of oxygen gas are there in 135 L of oxygen at STP?

6.02 mol

The molar mass of O2 is 32.0 grams, and the molar mass of magnesium is 24.30 grams. How many grams of oxygen are required to burn 10.0 g of magnesium if the reaction of the two elements creates magnesium oxide?

6.61 grams

Lithium has two isotopes: 92.5% of the atoms are Lithium-7. The remaining atoms are Lithium-6. What is the average atomic mass of Lithium?

6.925

How many electrons can be contained in the second energy level of an atom? Correct Answer:

8

What is the maximum number of valence electrons a neutral atom can have?

8

Which of the following is a true statement regarding catalysts?

A catalyst can increase the rate of a chemical reaction.

Which of these observations would likely be an indication of a chemical change?

A change in odor when two substances are mixed

Which of the following materials should be classified as a mixture?

Air

What is the equilibrium expression for the chemical reaction represented by the equation? PCl3(s) + Cl2(g) <--> PCl5(s)

k = 1/[Cl2]

What is the equilibrium expression represented by the equation? 2HI(g) <--> H2(g) + I2(g)

k = [H2][I2]/[HI]2

What is the equilibrium expression for the chemical reaction represented by this equation? N2 + 3H2 <--> 2NH3

k = [N2][H2]3/[NH3]2

When aluminum is added to lead nitrate, a single replacement reaction occurs. Predict the products of this reaction.

lead and aluminum nitrate

Which of these forces has the least strength?

london dispersion force

What causes an atom to emit light that is detected in its emission spectrum?

movement of an electron to a lower energy level

Which of the following crystals would be MOST LIKELY to have a very low melting point?

nonpolar covalent molecular crystal

What differentiates the three isotopes of hydrogen?

number of neutrons

During a laboratory experiment Juanita observes a model of two bonded atoms. She is told the atoms are both non-metals. Which of the following is a valid conclusion?

she is looking at a model of a covalent bond