Answer: 2 significant figures in 6.4
Explanation:
Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
Rules for significant figures:
Digits from 1 to 9 are always significant and have infinite number of significant figures.
All non-zero numbers are always significant. For example: 654, 6.54 and 65.4 all have three significant figures.
All zero’s between integers are always significant. For example: 5005, 5.005 and 50.05 all have four significant figures.
All zero’s preceding the first integers are never significant. For example: 0.0078 has two significant figures.
All zero’s after the decimal point are always significant. For example: 4.500, 45.00 and 450.0 all have four significant figures.
Mass of beaker = 24.2 g
Mass of beaker + mass of water = 30.625 g
Mass of water = 30.625 - Mass of beaker = 30.625 - 24.2 = 6.4g
The rule apply for the addition and subtraction is :
The answer would contain same number of decimal places as there are in the least precise number present.
Thus there are 2 significant figures in mass of water which is 6.4 grams.
