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 burns a magnesium ribbon, producing a brilliant white flame and a fine white powder. This is an example of:

Accepted Answer

Chemical change

Question 4

A chemist observes a liquid forming 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 is this? (1 Cal = 1000 cal, 1 cal = 4.184 J)

Accepted Answer

$$7.53 	imes 10^5$ J

Question 7

During a chemical reaction in an insulated vessel, the solution's temperature decreases as energy is absorbed to break bonds. This process is:

Accepted Answer

An endothermic chemical reaction

Question 8

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

Accepted Answer

$$232^\circC$$

Question 9

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

Accepted Answer

40.3 grams

Question 10

Equal 50.0-gram masses of iron ($$C = 0.449 J/g$$·$$^\circC) $$and aluminum ($$C = 0.903 J/g$$·$$^\circC) $$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 gold ring from 22.0 $$^\circC to 145.0$$ $$^\circC. $$Gold's specific heat is $$C = 0.128 J/g$$·$$^\circC. $$How much heat energy is required?

Accepted Answer

$$246 J$$

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$ J

Question 13

Liquid helium liquefies at 4.20 K. What is this temperature in Celsius? (Use $$^\circC = K$$ $$- 273.15)$$

Accepted Answer

$$-268.95^\circC$$

Question 14

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

Accepted Answer

$$10.0^\circC$$

Question 15

A blacksmith drops an 85.0-gram copper chunk ($$C = 0.385 J/g$$·$$^\circC) $$into 200.0 grams of water ($$C = 4.184 J/g$$·$$^\circC). $$The water temperature rises by 4.50 $$^\circC. $$What is the net temperature change ($$\Delta T) of $$the copper?

Accepted Answer

$$-22.1^\circC$

Question 16

Which of the following best illustrates the Law of Conservation of Mass in 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 statement correctly distinguishes between temperature and heat?

Accepted Answer

Temperature is a measure of average kinetic energy, while heat is energy transferred between systems.

Question 18

A heavy metal weight is dropped from a rooftop. Which sequence best describes the energy transformations?

Accepted Answer

Potential energy → kinetic energy → thermal energy

Question 19

Which of the following is a heterogeneous mixture?

Accepted Answer

Undissolved sandy mud in ocean water

Chapter 3: Matter and Energy – Guided Chemistry Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard