The table shows the amount of radioactive element remaining in a sample over a period of time: What is the half-life of the element in hours?
Group of answer choices
a. 63 hours
b. 7 hours
c. 21 hours
d.14 hours

What is the volume occupied by 10.0 dm3 of gas at standard pressure after it has been compressedat constant temputure to 500.0 kpa?

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

For each of the following compounds, write the formula then predict whether it would be a strong, weak, or non-electrolyte when placed in di water. for the ionic compounds only, put (s) or (aq) after the forrmula formula strong, weak or non electrolyte? a calcium hydroxide b. silver carbonate c. lead(ii) sulfate d. phosphorus trifluoride e. sodium phosphide f barium sulfate g. strontium acetate h. zinc nitrate