Question

the mass of 1 atom of hydrogen is 1.67 * 10^(-24) gram. how much do 25 atoms of hydrogen weigh?

A. 4.175 * 10^(-23) gram
B. 4.175 * 10^(-25) gram
C. 6.68 * 10^(-22) gram
D. 6.68 * 10^(-26) gram

Answer 1

25 * 1.67 * 10^(-24)
= 41.75 * 10^-24
= 4.175 * 10^-23

most scientific calculators can easily handle
operations with scientific notation numbers.
look for a key labeled : Exp
On mine, I could have done this:
1.67, Exp, 24, ± , =, x, 25, =
to get 4.175 <super> -23 </super>

Answer 2

so witch answer is it

Answer 3

oops, last line should read

to get 4.175 ^-23

Answer 4

is it A?

Answer 5

ok thx