Question 1

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout and the different parts are not visible.

Question 2

A sample of air is best classified as which of the following?

Accepted Answer

A homogeneous mixture

Question 3

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

Accepted Answer

Iron rusting in an old car

Question 4

A gold ring is hammered into a thin sheet. This is an example of:

Accepted Answer

A physical change

Question 5

Which of the following statements about the Kelvin temperature scale is correct?

Accepted Answer

It has no negative temperatures and 0 K represents absolute zero.

Question 6

Convert a body temperature of $$37.0\ ^\circ\mathrm{C} to $$Kelvin.

Accepted Answer

$$310\ \mathrm{K}$$

Question 7

A patient with hypothermia has a body temperature of $$34.0\ ^\circ\mathrm{C}. $$What is this temperature in degrees Fahrenheit? (Use $$F = 1.8C + 32)$$

Accepted Answer

$$93.2\ ^\circ\mathrm{F}$$

Question 8

Which of the following best describes potential energy?

Accepted Answer

Energy stored due to position or chemical composition, such as water at the top of a dam.

Question 9

How many kilocalories are in a cup of whole milk containing 13 g of carbohydrate, 9.0 g of fat, and 9.0 g of protein? (Use: $$4\ \mathrm{kcal/g}$$ for carbohydrate and protein, $$9\ \mathrm{kcal/g}$$ for fat. Round to the tens place.)

Accepted Answer

$$170\ \mathrm{kcal}$$

Question 10

A pat of butter provides $$150\ \mathrm{J} of $$energy when metabolized. How many calories is this? (Use $$1\ \mathrm{cal} = 4.184\ \mathrm{J})$$

Accepted Answer

$$36\ \mathrm{cal}$$

Question 11

Which of the following statements about specific heat is true?

Accepted Answer

Specific heat is the amount of heat required to raise the temperature of $$1\ \mathrm{g} of a $$substance by $$1\ ^\circ\mathrm{C}.$$

Question 12

If $$24.8\ \mathrm{g} of a $$metal absorbs $$275\ \mathrm{J} of $$energy and its temperature rises from $$21.0\ ^\circ\mathrm{C} to$$ $$56.6\ ^\circ\mathrm{C}$$, what is the specific heat of the metal? (Use $$q = m c \Delta T)$$

Accepted Answer

$$0.32\ \mathrm{J/g\ ^\circ C}$$

Question 13

How many joules are needed to melt $$32.0\ \mathrm{g} of $$ice at $$0\ ^\circ\mathrm{C}$$? (Heat of fusion for water: $$334\ \mathrm{J/g})$$

Accepted Answer

$$10,700\ \mathrm{J}$$

Question 14

Which process describes the direct change from a solid to a gas without passing through the liquid state?

Accepted Answer

Sublimation

Question 15

How many kilojoules are released when $$50.0\ \mathrm{g} of $$steam condenses at $$100\ ^\circ\mathrm{C}$$? (Heat of vaporization for water: $$2260\ \mathrm{J/g})$$

Accepted Answer

$$113\ \mathrm{kJ}$$

Question 16

A plateau (horizontal line) on a heating curve represents:

Accepted Answer

A change of state at constant temperature

Question 17

When a volcano erupts, $$175\ \mathrm{g} of $$steam at $$100\ ^\circ\mathrm{C} is $$released. How many kilojoules are lost when the steam condenses and then freezes at $$0\ ^\circ\mathrm{C}$$? (Heat of vaporization: $$2260\ \mathrm{J/g}$$, heat of fusion: $$334\ \mathrm{J/g})$$

Accepted Answer

$$528\ \mathrm{kJ}$$

Question 18

Which of the following best explains why sand in the desert is hot during the day and cool at night?

Accepted Answer

Sand has a low specific heat, so it heats up and cools down quickly.

Question 19

Which of the following is a physical property of copper?

Accepted Answer

It is an excellent conductor of heat and electricity.

Matter and Energy: Classification, Properties, and Changes

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