Q: If $$1.00 \times 10^4$\ \mathrm{g} of $$water is heated from $$25.0\ ^\circ \mathrm{C} to$$ $$45.0\ ^\circ \mathrm{C}$$, how much energy (in calories) is absorbed? (Specific heat of water = $$1.000\ \mathrm{cal/g\cdot ^\circ C})$$

$$2.00 \times 10^5$\ \mathrm{cal}$$

Question 1

Which of the following best describes a physical change?

Accepted Answer

Melting ice by adding energy

Question 2

Energy is defined as:

Accepted Answer

The capacity to do work

Question 3

Which of the following statements about calories and joules is correct?

Accepted Answer

1 Calorie (Cal) is equal to 1000 calories (cal)

Question 4

What is the specific heat of water in $$\mathrm{J/g\cdot ^\circ C}$$?

Accepted Answer

$$4.184\ \mathrm{J/g\cdot ^\circ C}$$

Question 5

A calorimeter is used to:

Accepted Answer

Measure the energy released or absorbed during a chemical or physical change

Question 6

If $$1.00 	imes 10^4$\ \mathrm{g} of $$water is heated from $$25.0\ ^\circ \mathrm{C} to$$ $$45.0\ ^\circ \mathrm{C}$$, how much energy (in calories) is absorbed? (Specific heat of water = $$1.000\ \mathrm{cal/g\cdot ^\circ C})$$

Accepted Answer

$$2.00 	imes 10^5$\ \mathrm{cal}$$

Question 7

Which of the following equations correctly calculates the heat absorbed or released by a substance?

Accepted Answer

$$q = m \cdot c \cdot \Delta T$$

Question 8

A 50.0 g sample of iron ($$c = 0.449\ \mathrm{J/g\cdot ^\circ C}) is $$heated from $$20.0\ ^\circ \mathrm{C} to$$ $$80.0\ ^\circ \mathrm{C}. $$How much energy (in joules) is absorbed?

Accepted Answer

$$1,347\ \mathrm{J}$$

Question 9

Which of the following is a chemical change?

Accepted Answer

Burning gasoline

Question 10

If $$100.0\ \mathrm{g} of $$aluminum ($$c = 0.901\ \mathrm{J/g\cdot ^\circ C}) $$absorbs $$1,802\ \mathrm{J} of $$heat, what is the temperature change $$\Delta T$$?

Accepted Answer

$$2.0\ ^\circ \mathrm{C}$$

Question 11

Which of the following statements about specific heat is true?

Accepted Answer

Water has a higher specific heat than iron.

Question 12

A student claims that tearing paper is a chemical change because it requires energy. Which is the best response?

Accepted Answer

Tearing paper is a physical change because the molecular structure remains the same.

Question 13

Which of the following best explains why metals are good conductors of heat?

Accepted Answer

Metals have free-moving electrons that transfer energy efficiently.

Question 14

A nutrition label states that a snack contains 150 Calories. How much energy is this in joules? ($$1\ \mathrm{cal} = 4.184\ \mathrm{J})$$

Accepted Answer

$$627,600\ \mathrm{J}$$

Question 15

Which real-life scenario best illustrates the concept of specific heat?

Accepted Answer

A metal spoon heating up quickly in hot soup

Question 16

If $$500.0\ \mathrm{g} of $$ethanol ($$c = 2.43\ \mathrm{J/g\cdot ^\circ C}) is $$cooled from $$60.0\ ^\circ \mathrm{C} to$$ $$20.0\ ^\circ \mathrm{C}$$, how much heat is released?

Accepted Answer

$$48,600\ \mathrm{J}$$

Quantifying Energy in Chemistry: Physical and Chemical Changes, Units, and Calorimetry

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