Which instrument would be used to measure the mass of a small stone?
I
1. graduated cylinder
2. Celsius thermometer
3. triple-beam balance
4. metric ruler

3. Triple Beam Balance

Explanation:

A triple beam will be most suitable for measuring the mass of a small stone because it is very accurate, and has a reading error of +/- 0.05 gram.

a is the correct answer

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