Question 2 of 10 Why is the average atomic mass used when calculating grams of a
substance?
A. The elements in the substance are mixtures of their isotopes.
B. The average atomic mass is known to more significant figures.
C. The number of isotopes in the sample is constantly changing.
D. The exact weights of the isotopes are not known.
SUBMIT

c.

explanation:

i believe the answer is true.

here is table 2-2:

country

percent of eligible voters that voted

rank

united states

44.9%

138

canada

60.1%

107

costa rica

84.6%

14

hungary

66.9%

82

japan

57.0%

118

egypt

27.7%

159

south africa

85.5%

10

ans is no, the data set cannot be plotted as a single circle graph

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.