Do all samples of specific substances have the same chemical composition?

Ca+O2➡CaO what is the balance chemical equation

Which of the following is true about phase changes? Evaporation occurs when a solid changes into a gas. Condensation occurs when a gas changes into a liquid. Sublimation occurs when a solid changes to a liquid.

The boundary where two air masses meet is called a

How could you separate mixtures

You need 70.2 J to raise the temperature of 34.0g of ammonia, NH3 (g), from 23.0C to 24.0C. Calculate the specific heat of ammonia.

Assuming that air contains 78 percent N2, 21 percent O2 and 1 percent Ar, all by volume. How many molecules of each type of gas are present in 1.0 L of air at STP?

Two children are playing tag. Child A who is doing the chasing can run 100m in 24 seconds Child B is running away from child A and can run 64m in 21 seconds.

What ion does a base increase

What is the definition of Amplitude?

An excess of NiCO3, 12 g, was added to 40cm cube of sulpheric acid, 2.0 mol/dm cube. The unreacted nickel carbonate was filtered out and the filtrate evaporated to optain the crystals.