a radioactive substance has a half-life of 10 years. if you start with 30 grams of the substance, how much will remain after 30 years.

A 2.425 g sample of a new organic material is combusted in a bomb calorimeter. The temperature of the calorimeter and its contents increase from 24.91 ∘ C to 30.28 ∘ C. The heat capacity (calorimeter constant) of the calorimeter is 28.

Metals are very good conductors of electricity, while nonmetals are not. What does this say about the metalloids? A. They are more like nonmetals and similarly cannot conduct electricity well. B.

What properties do elements found in groups 1B-8B on the periodic table display?

A gas sample has a volume of 222 mL at 55.0 °C and 100.0 kPa pressure. Find the volume at 20.0 °C and 75.5 kPa.

NaCl+CaS=Na^2S+CaCl^2 balance

A chemist determined by measurements that. 040 moles of gold participated in a chemical reaction. calculate the mass of gold that participated in the chemical reaction. round your answer to significant digits.

10) A screwdriver has the density of 5.5 grams per cubic centimeter. It also has the mass of 2.3 grams. What is the screwdriver's volume?

A chemist weighed out 20.7 g of sodium. Calculate the number of moles of sodium she weighed out

If 1.00 mol of argon is placed in a 0.500-L container at 20.0 ∘C, what is the difference between the ideal pressure (as predicted by the ideal gas law) and the real pressure (as predicted by the van der Waals equation) ? For argon, a=1.

Part 2: Finding Speed and Height Using Energy Directions: Use the KE and GPE equations to solve for speed or height depending on the situation. 1. A 1,000-kg car has 50,000 joules of kinetic energy. What is its speed? 2.