If you start with 5 molecules of O2 in the reaction 2Mg+O2--> 2MgO, how much Mg will you need?

a.

4

c.

8

b.

5

d.

10

What does a strong nuclear force do in an atom? It repels electrons from other electrons. It repels protons from other protons. It attracts protons and neutrons. It attracts protons and electrons.

What is the formula of solid ice?

Why do sunspots appear darker than their surroundings? A. They are masked by dust and gas passing between Earth and the Sun. B. They are warmer than their surrounding environment. C. They are cooler than their surrounding environment. D.

What is the metric unit for mass? a. Meters b. Kilograms c. Pounds d. matter

At 325 k, the pressure inside a gas-filled container is 467 kpa. If the pressure inside decreases to 233 kpa, but the volume remains the same, what is the final temperature of the gas?

Students measuring the mass of a rock record 6.759 g, 6.786 g, 6.812 g, and 6.779 g. Which other measurement of the block's mass would be most precise? A. 6.702 g B. 6.781 g C. 6.605 g D. 6.858 g

What two elements make up dihydrogen monoxide?

What did scientists observe using the earliest microscopes

Which statement describes the redox reaction that occurs when an object is electroplated? A. It is spontaneous and requires an electric current. B. It is spontaneous and produces an electric current. C.

How are electromagnetic different than all other waves