Why is an element considered a pure substance?

How many grams of lead (II) iodide are produced from 6.000 moles of NaI according to the balanced equation: Pb (NO3) 2 + 2 NaI à 2 NaNO3 + PbI2

What traits do synthesis and decomposition share?

assume that you used a 0.660 g piece of pure aluminum in the synthesis of alum and obtained a 63.5% yield of alum. How many grams of alum did you obtain?

Calculate the number of molecules in 4.56-g of lead (ii) nitrite

What event started the Gulf War in 1991? A. the invasion of Kuwait by Iraq B. the invasion of Pakistan by India C. the invasion of Egypt by Great Britain D. the invasion of Afghanistan by the Soviet Union

What is the specific heat capacity of a 17.5g sample of an unknown metal that releases 6700J of heat when it cools from 90 to 25 degrees C?

How can equilibrium of a closed system chemical reaction be disturbed? Select all that apply. Adding or removing products or reactants. Keeping the concentration of products and reactants the same. Keeping the temperature of the system constant.

Why does an exothermic reaction need activation energy?

The temperature of 15 grams of water increases by 3.0 degress. how much heat was absorbed by water?

What are the four types of stoichiometry problems?