Question 1

Which one is chemical change?

Accepted Answer

A chemical change involves a chemical reaction, where one or more substances are transformed into a new substance. Option B fits this definition as the heat from the roasting causes the marshmallow's sugars to undergo a chemical reaction, turning it from white to brown and giving it a different taste and texture. The other options are physical changes: A is a phase change, B is a chemical change, C is evaporation, and D is a phase change.

Question 2

Why does the U.S.ship its used electronics oversees?

Accepted Answer

Many other countries have more lax environmental regulations, and labor is cheaper. Shipping used electronics to other countries for disposal allows companies to save money on labor and disposal costs. Additionally, some countries may have more lenient environmental laws making it easier and cheaper for companies to dispose of their electronic waste.

Question 3

When water transitions from a liquid to a gas, which of the following statements is false?

Accepted Answer

When water transitions from a liquid to a gas, the liquid molecules do not necessarily have to be at the top of the container before they transition. The other statements (A, B, and C) are true.

Question 4

An aerosol is

Accepted Answer

An aerosol is a mixture of small solid or liquid particles suspended in air or gas. Examples of aerosols include hairspray, spray paint, and fog.

Question 5

Why is the disposal method used for the plastic components of electronics hazardous?

Accepted Answer

When plastic components of electronics are disposed of, they are often melted down, which can release toxic fumes into the air. These fumes can be harmful to both human health and the environment if not properly controlled. Therefore, the disposal method used for plastic components of electronics is hazardous.

Question 6

Would the evaporation of water from a mixture of salt water be considered a chemical change?

Accepted Answer

Evaporation of water from a mixture of salt water is a physical change as only the phase of water is changing, but not its chemical composition. The salt remains the same and does not undergo any chemical reaction or transformation during the process of evaporation. Therefore, option C is the correct answer.

Question 7

Which three toxic elements are part of e-waste?

Accepted Answer

The three toxic elements that are commonly found in e-waste are lead (Pb), mercury (Hg), and cadmium (Cd). These elements can cause serious environmental and health problems if not properly disposed of. Therefore, it is important to handle e-waste responsibly and recycle it through certified e-waste management programs. Options A, B, and C do not include the correct toxic elements commonly found in e-waste.

Question 8

Mixtures can often be separated into pure substances by taking advantage of differences in the physical properties of the pure substances contained in the mixture.Which one is not a physical property?

Accepted Answer

Flammability is a chemical property, not a physical property. Physical properties are characteristics that can be observed or measured without changing the identity of the substance, while chemical properties describe how a substance reacts with other substances to form new substances.

Question 9

Which of the following would be considered a physical change?

Accepted Answer

Solid dry ice sublimating into carbon dioxide gas is a physical change because it involves a change in state from solid to gas without altering the chemical composition of the substance.

Question 10

Which of the following retains its shape if it is transferred from one container to another?

Accepted Answer

Sodium metal retains its shape when transferred from one container to another because it is a solid under standard conditions. Gases like chlorine and neon will expand to fill their new containers, and liquids like ammonia will take the shape of their new container.

Quiz 3: Everything the Ways We Organize and Classify Matter