Which of these is true of a chemical reaction

a. Energy is either released or absorbed.

b. Energy is always absorbed.

c. Energy is always released.

d. Energy is not transferred.

A sample of tap water contains 1.95 x 10^3 ppm caco3. assuming the density of the tap water is 1.00 g/ml, calculate the mass of calcium carbonate in 2.0 l of water

What is the mass of 8.90 moles of magnesium chloride, MgCl2? Express your answer numerically in grams.

If the atomic number of an element is 6 and its mass number is 20, how many neutrons are in the atom's nucleus?

A sample of a radioactive isotope initially contains 20 x 10^10 atoms. After 16 days, 5 x 10^10 atoms remain. what is the half-life of the isotope? A) 12 days B) 20 days C) 10 days D) 16 days E) 8 days

What term is defined as splitting large nuclei into smaller ones

7. A perfect cube has a width of 2 cm. What is the cube's volume? Show your work!

Predict at least two circumstances (outside influences) that would cause a system in equilibrium to change the concentrations of its reactants or products.,

How many atoms are there in 2.3 grams of H?

Which of the following would dissolve in water, and why? None of these substances would dissolve in water Candle wax, it is a nonpolar substance Motor oil, its primary IMF is London Dispersion Forces Acetic acid, it ionizes into ions when added to

Have a region surrounding the central area called