Which substance is NOT a compound?

a. salt

b. sodium

c. pure water

d. carbon monoxide

Which substance can not be decomposed by a chemical change? A. Ammonia B. Carbon C. Methane D. Water

Calcium reacts with sulfur forming calcium sulfide. What is the theoretical yield (g) of CaS (s) that could be prepared from 8.54 g of Ca (s) and 2.33 g of sulfur (s) ? Do not type units with your answer.

Ryan saws some more wood from the top of the pyramid. The cross section moves closer to the base of the pyramid. What happens to the size and shape of the cross section when compared with the cross section in part A?

Which statement about ribosomes is correct? Prokaryotic ribosomes are larger than eukaryotic ribosomes. Prokaryotic ribosomes are smaller than eukaryotic ribosomes. Prokaryotic and eukaryotic ribosomes are same in size.

What is the word equation for the reaction between magnesium oxide and hydrochloric acid

The term southern oscillation most nearly refers to

Which kelvin temperature is equivalent to 20°C

When a piece of magnesium metal is added to hydrochloric acid, what gas is produced?

A 10 pound block of lead-210 has a half-life of 22 years. What percentage of the block still contains lead-210 after 60 years? 1.5% 15% 77% 27%

Combined gas law problem: a balloon is filled with 500.0 mL of helium at a temperature of 27 degrees Celsius and 755 mmHg. As the balloon rises in the atmosphere, the pressure and temperature drop.