Chemistry 6

What are the three ways a chemical can enter your body?

• Skin absorption, indigestion, inhalation

• Skin absorption, ingestion, annihilation

• Skin absorption, digestion, inhalation

• Skin absorption, ingestion, inhalation

Answer explanation

The correct answer is 'Skin absorption, ingestion, inhalation' because these are the primary routes through which chemicals can enter the body. 'Annihilation' is not a valid method, and 'digestion' is not the same as 'ingestion'.

The mass of a liquid substance is 0.95 g. Students measured the mass as 0.56 g, 0.55g, and 0.57 g. Which best describes the students’ measurements?

• accurate but not precise

• precise but not accurate

• both precise and accurate

• neither accurate nor precise

Answer explanation

The students' measurements (0.56 g, 0.55 g, 0.57 g) are close to each other, indicating precision. However, they are significantly lower than the actual mass (0.95 g), showing a lack of accuracy. Thus, they are precise but not accurate.

What is the name of the piece of equipment shown?

• Beaker

• Erlenmeyer Flask

• Graduated Cylinder

• Volumetric Flask

Answer explanation

The equipment shown is a beaker, which is a common laboratory container used for mixing, stirring, and heating liquids. It is characterized by its cylindrical shape and spout for easy pouring.

Oxygen gas (O2) is an example of what type of substance?

• Compound

• Heterogeneous Mixture

• Element

• Homogeneous Mixture

Answer explanation

Oxygen gas (O2) consists of two oxygen atoms bonded together, making it a diatomic molecule. Since it is made of only one type of atom, it is classified as an element, not a compound or mixture.

Which of the following states of matter does not have a definite shape but does have a definite volume?

• Solid

• Liquid

• Gas

• Plasma

Answer explanation

A liquid does not have a definite shape, meaning it can take the shape of its container, but it does have a definite volume, maintaining the same amount of space regardless of the container's shape.

When a solid changes to a gas, it is called:

• Deposition

• Vaporization

• Sublimation

• Freezing

Answer explanation

When a solid changes directly to a gas, this process is called sublimation. Unlike vaporization, which involves a liquid turning into a gas, sublimation skips the liquid phase entirely.

Tags

NGSS.MS-PS1-4

Calculate density of a substance if its mass is 240. hg and its volume is 120. cm3.

• 2.0 hg/cm3

• 20.0 hg/cm3

• 0.5 hg/cm3

• 0.50 hg/cm3

Answer explanation

Density is calculated as mass divided by volume. Here, mass = 240 hg and volume = 120 cm³. Thus, density = 240 hg / 120 cm³ = 2.0 hg/cm³. Therefore, the correct answer is 2.0 hg/cm³.

Which subatomic particle is not found in the nucleus?

• Proton

• Electron

• Neutron

• All are found in the nucleus

Answer explanation

The electron is a subatomic particle that orbits the nucleus of an atom, while protons and neutrons are found within the nucleus itself. Therefore, the correct answer is the electron.

How many neutrons does Chlorine-37 have?

• 17

• 18

• 20

• 37

Answer explanation

Chlorine-37 has a mass number of 37. The atomic number of chlorine is 17, which means it has 17 protons. To find the number of neutrons, subtract the number of protons from the mass number: 37 - 17 = 20. Thus, Chlorine-37 has 20 neutrons.

How many protons does 80Se have?

• 34

• 45

• 46

• 80

Answer explanation

The element symbol 'Se' represents selenium, which has an atomic number of 34. This atomic number indicates the number of protons in an atom of selenium, making 34 the correct answer.