Q: A nutrition label states that a serving contains 180 Cal. How many joules (J) of energy does this correspond to? (1 Cal = 1000 cal, 1 cal = 4.184 J)

$$7.53 \times 10^5$\ \text{J}$$

Q: A laboratory hotplate consumes 1.45 kWh of energy. Convert this to Joules (J). (1 kWh = $$3.60 \times 10^6$ J)

$$5.22 \times 10^6$\ \text{J}$$

Question 1

A sample of matter consists of particles tightly packed in a well-ordered, repeating three-dimensional array. Which classification best describes this sample?

Accepted Answer

Crystalline solid

Question 2

Which of the following substances is a pure element, not a compound?

Accepted Answer

Pure gaseous helium in a balloon

Question 3

A student observes magnesium metal burning with a brilliant white flame to produce a fine white powder. This transformation is an example of:

Accepted Answer

Chemical change

Question 4

A chemist analyzes a liquid that forms two distinct layers with a visible boundary after sitting. This system is best categorized as:

Accepted Answer

Heterogeneous mixture

Question 5

The boiling point of liquid nitrogen is 77 Kelvin. This statement describes:

Accepted Answer

A physical property

Question 6

A nutrition label states that a serving contains 180 Cal. How many joules (J) of energy does this correspond to? (1 Cal = 1000 cal, 1 cal = 4.184 J)

Accepted Answer

$$7.53 	imes 10^5$\ 	ext{J}$$

Question 7

During a chemical reaction in an insulated vessel, the internal temperature of the solution decreases as thermal energy is absorbed to break chemical bonds. This process is best classified as:

Accepted Answer

An endothermic chemical reaction

Question 8

An industrial oven records a temperature of 482 °F. What is this temperature in Celsius (°C)? (Use $$T_{	ext{C}} = \frac{5}{9}(T_{	ext{F}} - 32))$$

Accepted Answer

$$232\ ^\circ	ext{C}$$

Question 9

According to the Law of Conservation of Mass, if 24.3 grams of magnesium reacts with 16.0 grams of oxygen, what mass of magnesium oxide is produced?

Accepted Answer

$$40.3\ 	ext{grams}$$

Question 10

Equal 50.0-gram masses of iron ($$C = 0.449\ 	ext{J/g} \cdot ^\circ	ext{C}) $$and aluminum ($$C = 0.903\ 	ext{J/g} \cdot ^\circ	ext{C}) $$are heated with 500 J. Which statement is correct?

Accepted Answer

The iron sample will experience a larger increase in temperature because it has a lower specific heat capacity.

Question 11

A jeweler heats a 15.5-gram ring of pure gold from 22.0 °C to 145.0 °C. Given $$C = 0.128\ 	ext{J/g} \cdot ^\circ	ext{C}$$, how much heat energy is required? (Use $$q = mC\Delta T)$$

Accepted Answer

$$246.7\ 	ext{J}$$

Question 12

A laboratory hotplate consumes 1.45 kWh of energy. Convert this to Joules (J). (1 kWh = $$3.60 	imes 10^6$ J)

Accepted Answer

$$5.22 	imes 10^6$\ 	ext{J}$$

Question 13

Liquid helium liquefies at 4.20 K. What is this temperature in Celsius? (Use $$T_{	ext{C}} = T_{	ext{K}} - 273.15)$$

Accepted Answer

$$-268.95\ ^\circ	ext{C}$$

Question 14

A 250.0-gram sample of a compound ($$C = 1.85\ 	ext{J/g} \cdot ^\circ	ext{C}) $$absorbs 4,625 J. What is the net temperature change $$\Delta T$$? (Use $$\Delta T = \frac{q}{mC})$$

Accepted Answer

$$9.99\ ^\circ	ext{C}$$

Question 15

A blacksmith drops an 85.0-gram chunk of copper ($$C = 0.385\ 	ext{J/g} \cdot ^\circ	ext{C}) $$into 200.0 grams of water ($$C = 4.184\ 	ext{J/g} \cdot ^\circ	ext{C}). $$The water temperature rises by 4.50 °C. What is the net temperature change $$\Delta T of $$the copper? (Assume all heat lost by copper is gained by water.)

Accepted Answer

$$22.1\ ^\circ	ext{C}$$

Question 16

Which of the following best illustrates the Law of Conservation of Mass during a chemical reaction?

Accepted Answer

The total mass of reactants equals the total mass of products, even if the substances change form.

Question 17

Which scenario best demonstrates a physical change rather than a chemical change?

Accepted Answer

Melting ice into liquid water

Question 18

A heavy metal weight is carried to the roof of a building and dropped. Which energy transformation occurs as it falls and hits the ground?

Accepted Answer

Potential energy converts to kinetic energy, then to thermal energy upon impact.

Question 19

Which of the following is a heterogeneous mixture?

Accepted Answer

Undissolved sandy mud in a bucket of ocean water

Chapter 3: Matter and Energy – Guided Chemistry Study

Study Guide - Practice Questions

Study Guide - Flashcards