Chem Mid-Term Practice_INTRO TO CHEM

How many significant figures are in the measurement 0.0103 mL?

• 2

• 3

• 4

• 5

Answer explanation

In the measurement 0.0103 mL, the leading zeros are not significant. The digits 1, 0, and 3 are significant, giving a total of 3 significant figures. However, the trailing zero after the decimal point counts as significant, resulting in 4 significant figures.

How many significant figures are in the measurement 760 mmHg?

• 0

• 1

• 2

• 3

Answer explanation

The measurement 760 mmHg has three significant figures. The digits 7, 6, and 0 are all significant because the zero is trailing in a whole number with a decimal context, indicating precision.

Which of the following is an example of a qualitative observation?

• The shirt is red.

• The shirt has a mass of 15 grams.

• The shirt is 72 cm long.

• The shirt is ugly.

Answer explanation

The correct choice, 'The shirt is red,' is a qualitative observation as it describes a characteristic of the shirt based on color. In contrast, the other options provide quantitative measurements.

Matter with an indefinite shape but a definite volume would be considered a _______.

• solid

• liquid

• gas

• plasma

Answer explanation

Matter with a definite volume but an indefinite shape is classified as a liquid. Liquids take the shape of their container while maintaining a constant volume, unlike solids (definite shape and volume) or gases (indefinite shape and volume).

Tags

NGSS.MS-PS1-4

A property of matter that depends on the amount of matter present would be considered a(n) _______ property.

• physical

• chemical

• intensive

• extensive

Answer explanation

An extensive property depends on the amount of matter present, such as mass and volume. In contrast, intensive properties, like density and color, do not change with the amount of substance. Therefore, the correct answer is extensive.

A solution where the solvent is water is known as a(n) _______.

• aqueous solution

• alloy

• solute

• substance

Answer explanation

A solution where the solvent is water is specifically called an 'aqueous solution'. The other options do not refer to solutions with water as the solvent.

Mical tells his mom he can’t go to school today to take his chemistry test because he is running a temperature of 310.2 K. What is his temperature in degrees Fahrenheit?

• -11.4 °F

• 2.81 °F

• 37.1 °F

• 98.7 °F

Answer explanation

To convert from Kelvin to Fahrenheit, use the formula F = (K - 273.15) × 9/5 + 32. For 310.2 K, this results in approximately 98.7 °F, making it the correct answer.

Which of the following is not an example of a physical change?

• Cutting a piece of string in half.

• Freezing water into an ice cube.

• Crumpling a piece of paper into a ball.

• Letting the food in your lunch box rot in your locker.

Answer explanation

Letting food rot is a chemical change due to decomposition, while the other options involve changes in form or state without altering the substance itself, which are physical changes.

Which of the following statements about a chemical change is true?

• A chemical change results in a change in energy AND a change in the amount of matter.

• A chemical change results in a change in energy but not a change in the amount of matter.

• A chemical change results in a change in the amount of matter but not a change in energy.

• A chemical change results in neither a change in energy OR a change in the amount of matter.

Answer explanation

A chemical change involves the rearrangement of atoms, leading to new substances. This process typically involves energy changes (like heat) but conserves mass, meaning the total amount of matter remains constant.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following measurements would be considered the smallest?

• 10,000 ug

• 1,000 hg

• 100 cg

• 10 g

Answer explanation

To compare the measurements, convert them to grams: 10,000 ug = 0.01 g, 1,000 hg = 100 g, 100 cg = 1 g, and 10 g = 10 g. The smallest measurement is 10 g.