A student mixes two water solutions with an initial temperature of 25.0°C
to form a final solution with a mass of 65.0 g at 30.0°C. What is the heat
change, in kJ, for this reaction?

325 kJ
272 kJ
1.36 kJ
1.95 kJ

Agas in a balloon at constant pressure has a volume of 160 ml at -125*c. what is its volume at 29.0*c?

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.)

If you burn 46.6 g of hydrogen and produce 416 g of water, how much oxygen reacted