How much heat is released if 7.15 g cao(s) is added to 152 g of h2o(l)? cao(s) + h2o(l) → ca(oh)2(s) δh°rxn = –64.8 kj/mol?

What semimetal can form four single covalent bonds.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

Predict the reactants of this chemical reaction. that is, fill in the left side of the chemical equation. be sure the equation you submit is balanced. (you can edit both sides of the equation to balance it, if you need to.) note: you are writing the molecular, and not the net ionic equation. > cacl2(aq) + h20(l)