Chemistry Review

The following statements related to a mole EXCEPT

• A mole is used to simplify the counting of atoms.

• Representative particles can only be atoms.

• A mole is used to simplify the counting of electrons.

Answer explanation

The correct choice is 'Representative particles can only be atoms.' This is false because representative particles can also be molecules, ions, or formula units, not just atoms.

Tags

NGSS.HS-PS1-7

Abby, Jonathan, and Harmony are in a science class learning about different ways to measure ingredients for a recipe. The following are the three basic ways they can quantify the ingredients EXCEPT

• density

• volume

• shape

Answer explanation

The three basic ways to quantify matter are count, volume, and mass. Shape does not quantify matter; it describes the form of an object. Therefore, the correct answer is shape.

Ada and Harmony are counting the species present in a sample, usually atoms, molecules, or formula units. What are they counting?

• mole

• representative particles

• avogradro's number

Answer explanation

The term 'representative particles' refers to the species present in a substance, such as atoms, molecules, or formula units. This makes it the correct choice, as it directly addresses the question's focus on species in a substance.

Ada and Jake are in a science class learning about elements. Their teacher explains that there is a dimensionless quantity that represents the average mass of atoms of an element divided by 1/2 the atomic mass of carbon-12 atom. What is this quantity called?

• atomic weight

• molar mass

• mole

Answer explanation

The atomic weight is a dimensionless quantity that compares the average mass of an element's atoms to half the mass of a carbon-12 atom, making it the correct choice over molar mass or mole.

Kaitlyn and Damion are conducting an experiment in their chemistry class. They find that any two samples of gas with an equal number of particles have the same volume when they are held at the same pressure and temperature. What principle are they observing?

• Avogadro's hypothesis

• Charle's law

• Boyle's law

Answer explanation

Avogadro's hypothesis states that equal volumes of gases, at the same temperature and pressure, contain an equal number of particles. This directly supports the statement in the question, making it the correct choice.

Kaitlyn and Juan are comparing the mass and volume of different materials in their science class. They want to find out which material has the highest ratio of mass to volume. What is this ratio called?

• density

• mass

• volume

Answer explanation

The ratio of the mass of a substance to its volume is defined as density. Therefore, the correct answer is density, as it directly describes this relationship.

Ada and Jonathan are baking a cake, and they need to ensure that the ingredients are mixed in a fixed ratio by mass to get the perfect taste. This scenario is an example of which principle?

• the law of definite proportions

• percent composition

• percent by mass

Answer explanation

The law of definite proportions states that a compound always contains its component elements in a fixed ratio by mass, making it the correct choice for this question.

It states that any sample of a compound will be made up of the same elements in the same ratio

• the law of definite proportions

• law of constant composition

• percent composition

Answer explanation

The law of constant composition states that a compound always contains the same elements in the same fixed ratio, regardless of the sample size. This is why the correct answer is the law of constant composition.

Ty and Branson are conducting an experiment in their chemistry class. They need to measure the amount of solute that is dissolved in a given quantity of solvent to determine the solution's strength. What is this measurement called?

• concentration

• dilute solution

• solution

Answer explanation

The term 'concentration' specifically refers to the amount of solute dissolved in a solvent, making it the correct choice. A 'dilute solution' describes a solution with low concentration, while 'solution' is a broader term.

Tags

NGSS.HS-PS1-5

Kaitlyn and Anna are making lemonade. They add a small amount of sugar to the water.

• concentration

• dilute solution

• solution

Answer explanation

A solution with a small amount of solute is referred to as a dilute solution. This term specifically indicates that the concentration of solute is low compared to the solvent, making 'dilute solution' the correct choice.

Tags

NGSS.HS-PS1-5