Q: A refrigerator uses $$780 \text{ kWh} of $$electrical energy per year. How many kilocalories of electricity does it use in three years? ($$1 \text{ kWh} = 3.60 \times 10^6$ \text{ J}$$, $$1 \text{ kcal} = 4184 \text{ J})$$

$$2.0 \times 10^4$ \text{ kcal}$$

Q: If $$15.7 \text{ g} of $$silver raises its temperature by $$17.2 ^\circ \text{C}$$ when it absorbs $$6845.5 \text{ J}$$, what is its molar heat capacity? (Molar mass of Ag = $$107.87 \text{ g/mol})$$

$$25.0 \text{ J/mol} \cdot ^\circ \text{C}$$

Q: Which of the following represents a physical property?

Mercury is a silvery liquid at $$25^\circ \text{C}.$$

Question 1

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more different elements that are chemically bonded together.

Question 2

Which of the following is a homogeneous mixture?

Accepted Answer

Air

Question 3

A sample of copper absorbs $$3.53 	ext{ kJ} of $$heat, which increases the temperature by $$25 ^\circ 	ext{C}. If $$the specific heat capacity of copper is $$0.385 	ext{ J/g} \cdot ^\circ 	ext{C}$$, what is the mass (in kg) of the copper sample?

Accepted Answer

$$0.367 	ext{ kg}$$

Question 4

Which of the following is a physical change?

Accepted Answer

Tearing a piece of paper.

Question 5

Which of the following represents a chemical property of hydrogen gas?

Accepted Answer

It reacts explosively with oxygen gas.

Question 6

At what temperature is the temperature in degrees Fahrenheit equal to the temperature in degrees Celsius?

Accepted Answer

$$-40^\circ$$

Question 7

Which of the following substances will have the lowest observed viscosity?

Accepted Answer

Helium gas

Question 8

Which of the following is NOT a physical property?

Accepted Answer

An iron bar rusts.

Question 9

A refrigerator uses $$780 	ext{ kWh} of $$electrical energy per year. How many kilocalories of electricity does it use in three years? ($$1 	ext{ kWh} = 3.60 	imes 10^6$ 	ext{ J}$$, $$1 	ext{ kcal} = 4184 	ext{ J})$$

Accepted Answer

$$2.0 	imes 10^4$ 	ext{ kcal}$$

Question 10

Which of the following is a reversible change?

Accepted Answer

Melting a chocolate bar then re-solidifying it in the freezer.

Question 11

Which of the following statements deals with potential energy with nonchemical energy associated?

Accepted Answer

Your chemistry book sitting on a table counter near the trashcan weighing $$12 	ext{ N} at a $$height of $$1.2 	ext{ m}.$$

Question 12

Which of the following is a chemical change?

Accepted Answer

Cooking an egg

Question 13

If $$15.7 	ext{ g} of $$silver raises its temperature by $$17.2 ^\circ 	ext{C}$$ when it absorbs $$6845.5 	ext{ J}$$, what is its molar heat capacity? (Molar mass of Ag = $$107.87 	ext{ g/mol})$$

Accepted Answer

$$25.0 	ext{ J/mol} \cdot ^\circ 	ext{C}$$

Question 14

Which of the following represents a physical property?

Accepted Answer

Mercury is a silvery liquid at $$25^\circ 	ext{C}.$$

Question 15

How much heat (in kJ) is released when $$120.0 	ext{ g}$$ $$	ext{H}_2	ext{O}$$ goes from $$90^\circ 	ext{C} to$$ $$45^\circ 	ext{C}$$? The specific heat capacity of $$	ext{H}_2	ext{O} is$$ $$4.184 	ext{ J/g} \cdot ^\circ 	ext{C}.$$

Accepted Answer

$$18.8 	ext{ kJ}$$

Question 16

Which compound would show the greatest temperature change upon absorbing $$25.0 	ext{ J} of $$heat? (Assume all samples have a mass of $$250.0 	ext{ g})$$

Accepted Answer

Copper

Question 17

Nitric acid has a melting point of $$-42^\circ 	ext{C}$$ and a boiling point of $$83^\circ 	ext{C}. $$What is its physical state at $$110^\circ 	ext{C}$$?

Accepted Answer

Gas

Question 18

Which of the following is NOT a chemical property for an unknown element?

Accepted Answer

It has a yellow-orange color.

Question 19

Which of the following containers would have the greatest flow of thermal energy in the form of heat if all are at $$50^\circ 	ext{C}$$?

Accepted Answer

$$120 	ext{ g H}_2	ext{O}$$

Matter and Energy: Classification, States, and Properties

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