Indicate which of the following are exact numbers. (select all that apply.) 1.the number of microseconds in a week 2.the number of inches in a mile 3.the mass of a paper clip 4.the number of pages in a book 5.the surface area of a dime 6.the number of ounces in a pound

Exact numbers need not be measured. They can be counted. Conversion factors and countable units come under exact numbers. Measured quantities are measured using a device.

1) Number of microseconds in a week -Exact as it need not be measured. It can be estimated using the conversion factors between microseconds, seconds, minutes, hours, days and week.

2) Number of inches in a mile - Exact number as it is an established conversion factor.

3) The mass of a paper clip - Measured number as it has to measured using a weighing balance.

4) The number of pages in a book - Exact number as it is not measured. It can be counted.

5) Surface area of the dime-Measured number as it has to be measured.

6) The number of ounces in a pound-Exact number as it is a constant value.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.