Perform the following calculations, then round off each answer to the proper number of significant figures: 1210.0 g + 157.22 g - 30. g ( show work)

- 1337 g

Solution:- For mathematical operations we use PEMDAS. P stands for parenthesis off, E stands for exponents, M stands for multiplication, D stands for division, A stands for addition and S stands for subtraction. All the mathematical operations are done in this sequence.

What we have given in the problem is, 1210.0 g + 157.22 g - 30. g

Here we have addition and subtraction. As per the law, we will do addition first. In addition and subtraction we go with least number of decimal places.

1210.0 has one decimal place where as 157.22 has two decimal places, since the first number has least decimal places(one decimal place), the answer should also have only one decimal place.

1210.0 g + 157.22 g = 1367.2 g

Now, we will do subtraction. 30. does not have any decimal place and so on subtraction the final answer must not have any decimal places.

1367.2 g - 30. g = 1337 g

So, the final answer is 1337 g.

i belive it is water

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o