Which statement describes the transfer of heat energy that occurs when an ice cube is added to an insulated container with 100 milliliters of
water at 25°c?
(1) both the ice cube and the water lose heat energy.
(2) both the ice cube and the water gain heat energy.
(3) the ice cube gains heat energy and the water loses heat energy.
(4) the ice cube loses heat energy and the water gains heat energy.

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.)

Precision can be defined as the o exact center of a data set. o reproducibility of a measured value. o correlation between two variables that are measured in a data set agreement between a measured value and an accepted value.

What is the most important factor in determining climates.