in chemistry, how would you do this problems?

Question

convert 20kg to grams

convert 400mL to L

convert 12m to cm

convert 3.5 hours to seconds

also,

put 0.000,0067 kg to a scientific notation

Answer 1

20 kg = 20,000 gms
400 ml = 0.4 L
12m = 1200 cm
3.5 hours = 12600 seconds
0.0000067 kg = 6.7 x 10^-6 kg (which equals 6.7 x 10^-3 gms)

While the traditional notation of 6.7x10^-6 is still preferred where typography allows, 6.7E-6 is used as well; it's typographically easier to use the latter notation.

Answer 2

Q1
One kg has 1000g so
20kg=20*1000g

Q2
one meter has 100 cm
so 12m=12*100cm

Q2
hour has 60mins
1 min has 60secs
3.5 hrs=3.5*60*60secs

Writing something in scientifis notation means writing as a number between 1 and 10 and then multypplying by a power of ten to give the ogiginal number
so
0.0000067=6.7*10-6(ten to the power minus 6)
(write the number "-6" as super script.. that is above ten)

Answer 3

Lay thy hands on a friendly conversion table and do the first 3 yourself.

Scientific notation for this would be in the format
a.b x 10^-c. So move your decimal point to the right until you get the a.b. Count the number of "moves" you made to find c

Answer 4

20 kg = 20,000 gms

400 ml = 0.4 L

12m = 1200 cm

3.5 hours = 12600 seconds

0.0000067 kg = 6.7 x 10^-6 kg (which equals 6.7 x 10^-3 gms)

Answer 5

20,000 grams
.4 or 2/5 liters
1200 centimeters
12,600 seconds
i dont know the last one
hope i helped