Ethanol has a density of 0.789 g/cm3. What volume of ethanol in mL must be poured into a graduated cylinder to equal 21.9 g? Report your answer in standard notation with appropriate significant figures and do not include units. Complete the following arithmetic problem and report the answer to the correct number of significant figures. (Report your answer in standard notation.) 0.71 plus 81.8

Rules for significant figure 

All non zero integer are significant 

Exact number have unlimited number of significant figure

Zero between the non-zero number are significant 

Zero before non-zero integer are non significant

Zero after non-zero integer which are not followed by decimal are not significant

Zero after non zero integer which are followed by decimal point are significant

If zero come after non-zero integer and come after decimal point they are significant

While doing addition and subtraction , the answer should have same number of decimal point as that of limiting term. Limiting term is the number which have least decimal place

While doing multiplication and division the answer should have number of significant figure as that of limiting term. Limiting term is number with least number of significant figure

While converting units answer should have same number of significant figure as the number started with.