Q: A student heats 24.8 g of a metal, causing its temperature to rise from 20.2°C to 24.5°C, and the metal absorbs 275 J of energy. What is the specific heat of the metal?

$$SH = \frac{275}{24.8 \times 4.3} = 2.6\ \frac{J}{g\ ^\circ C}$$

Q: A cup of whole milk contains 12 g of carbohydrate, 9 g of fat, and 9 g of protein. How many kilocalories does a cup of whole milk contain? (Use: 4 kcal/g for carbohydrate, 9 kcal/g for fat, 4 kcal/g for protein)

$$12 \times 4 + 9 \times 9 + 9 \times 4 = 48 + 81 + 36 = 170\ \text{kcal}$$

Q: How many calories are obtained from a pat of butter if it provides 150 J of energy when metabolized? (Use: $$1\ \text{cal} = 4.184\ \text{J})$$

$$\frac{150}{4.184} = 36\ \text{cal}$$

Q: A 255 g sample of copper is heated from 24°C to 185°C. If the specific heat of copper is $$0.385\ \frac{J}{g\ ^\circ C}$$, how much energy (in kJ) is required?

$$255 \times (185 - 24) \times 0.385 = 15,758.175\ \text{J} = 15.8\ \text{kJ}$$

Q: How many kilojoules are needed to melt 32.0 g of ice at 0°C? (Heat of fusion for water = 334 J/g)

$$32.0 \times 334 = 10,688\ \text{J} = 10.7\ \text{kJ}$$

Question 1

Which of the following is an example of a homogeneous mixture?

Accepted Answer

Brass (copper and zinc)

Question 2

A sample contains only copper atoms. How is this sample best classified?

Accepted Answer

Element

Question 3

Which physical state of matter has particles that fill the entire volume of a container and move rapidly?

Accepted Answer

Gas

Question 4

Which of the following is a chemical property?

Accepted Answer

Ability to burn

Question 5

A student heats 24.8 g of a metal, causing its temperature to rise from 20.2°C to 24.5°C, and the metal absorbs 275 J of energy. What is the specific heat of the metal?

Accepted Answer

$$SH = \frac{275}{24.8 	imes 4.3} = 2.6\ \frac{J}{g\ ^\circ C}$$

Question 6

Which of the following changes is a chemical change?

Accepted Answer

Burning a candle

Question 7

What is the normal body temperature of 37°C in kelvins?

Accepted Answer

$$T_K = 37 + 273 = 310\ K$$

Question 8

A cup of whole milk contains 12 g of carbohydrate, 9 g of fat, and 9 g of protein. How many kilocalories does a cup of whole milk contain? (Use: 4 kcal/g for carbohydrate, 9 kcal/g for fat, 4 kcal/g for protein)

Accepted Answer

$$12 	imes 4 + 9 	imes 9 + 9 	imes 4 = 48 + 81 + 36 = 170\ 	ext{kcal}$$

Question 9

Which of the following best describes potential energy?

Accepted Answer

Energy stored due to position or chemical composition

Question 10

How many calories are obtained from a pat of butter if it provides 150 J of energy when metabolized? (Use: $$1\ 	ext{cal} = 4.184\ 	ext{J})$$

Accepted Answer

$$\frac{150}{4.184} = 36\ 	ext{cal}$$

Question 11

Which separation technique would be most effective for separating the pigments in ink?

Accepted Answer

Paper chromatography

Question 12

Which statement about the Kelvin temperature scale is correct?

Accepted Answer

0 K is the coldest temperature possible

Question 13

A 255 g sample of copper is heated from 24°C to 185°C. If the specific heat of copper is $$0.385\ \frac{J}{g\ ^\circ C}$$, how much energy (in kJ) is required?

Accepted Answer

$$255 	imes (185 - 24) 	imes 0.385 = 15,758.175\ 	ext{J} = 15.8\ 	ext{kJ}$$

Question 14

Which of the following statements about mixtures is true?

Accepted Answer

Mixtures can be separated by physical methods

Question 15

Which of the following substances has the highest specific heat?

Accepted Answer

Water, H$$_2O(l)$$

Question 16

How many kilojoules are needed to melt 32.0 g of ice at 0°C? (Heat of fusion for water = 334 J/g)

Accepted Answer

$$32.0 	imes 334 = 10,688\ 	ext{J} = 10.7\ 	ext{kJ}$$

Question 17

Which of the following is NOT a physical property?

Accepted Answer

Ability to rust

Question 18

A person loses weight when:

Accepted Answer

Food intake is less than energy output

Chapter 3: Matter and Energy – Structured Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard