Q: Which of the following is an example of a container that is filled with a pure substance rather than with a mixture? OPTIONS:
- a tire filled with air
- a jar filled with salt water
- a balloon filled with helium
- a glass filled with chocolate milk
A: a balloon filled with helium

When carbon and oxygen combine chemically, the mass of the product is
OPTIONS:
- greater than the mass of the carbon plus the mass of the oxygen
- equal to the mass of the carbon plus the mass of the oxygen
- equal to the mass of the carbon
- less than the mass of the carbon

equal to the mass of the carbon plus the mass of the oxygen

Q: In a copper wire, a temperature increase is the result of which of the following? ---- OPTIONS:
- an increase in the size of the copper particles
- a decrease in the mass of the copper particles
- an increase in the motion of the copper particles
- a decrease in the distance between the copper particles

A: an increase in the motion of the copper particles

Which of these best defines the term "pollutant"?
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OPTIONS:
- anything humans add to the atmosphere and oceans
- any substance that is harmful to the environment
- any substance that is a waste product of industry
- a substance that does not break down over time

any substance that is harmful to the environment

Question:
Tobias rode his bike on a road for a 2 hr period. On average, he passed a 1 km marker every 3 min during this period. Which of the following was his average speed for this 2 hr period?
OPTIONS:
- 10 km/hr
- 15 km/hr
- 20 km/hr
- 25 km/hr
Answer:
20 km/hr

*Question*: Which of the following describes how a microwave oven heats food? OPTIONS:
- The oven's interior reflects heat onto the food.
- The oven's interior, like a lens, focuses heat onto the food.
- Water molecules in the food reflect energy from microwave radiation.
- Water molecules in the food absorb the energy of microwave radiation.
*Answer*:
Water molecules in the food absorb the energy of microwave radiation.