A chemical or physical change that releases heat into its surroundings is ...

A. An exothermic process

B. melting ice

C. endothermic process

D. A phase change

C-12, c-13, and c-14 have the same number of protons but different numbers of neutrons so they are

The gas in an engine cylinder is compressed until it has a volume of 0.045 liter and an absolute pressure of 28 atmospheres. If the engine cylinder contains 0.020 mole of gas, what is its temperature? The temperature of the gas is how many K.

A 170 g sample of an aqueous alcohol solution contains 20.0% alcohol by mass. What is the mass of solvent present in the solution? 20 g 34g 136 g 170 g

Hydrogen has three naturally occurring isotopes which figure into the average atomic mass found on the periodic table (1.00974) : hydrogen-1, hydrogen-2, and hydrogen-3. Which would you guess is most abundant? Explain your answer

How to pick a lab partner?

Zircon is a mineral with the empirical formula ZrSiO4. If all the zirconium is 90Zr, all the silicon is 28Si, and all the oxygen is 16O, what mass of oxygen is present in 10. g of zircon?

Which property below is not a general property of metals: A. Ductile C. Malleable B. Poor conductor of heat D. High luster

Calculate the number of particles (atoms or molecules) of the following: 1. How many molecules are there in 24 grams of FeF3? 2. How many molecules are there in 450 grams of Na2SO4? 3. How many grams are there in 2.3 x 1024 atoms of silver?

Write a balanced equation for the decomposition reaction described, using the smallest possible integer coefficients. When calcium carbonate decomposes, calcium oxide and carbon dioxide are formed.

What is the atomic number of magnesium?