How many grams of CaCl2 are needed to make 644.5 g of a solution that is 29.0 % (m/m) CaCl2 in water

What kind of ion is contained in salts that produce an acidic solution? a positive ion that attracts a proton from water a positive ion that releases a proton to water a negative ion that attracts a proton from water a negative ion that releases a proton to water

What is the polyatamic ion of borate

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.)