Question

If you add 50.0 ml to a beaker containing 22ml of water, how much total water do you have in the beaker?
(A) 72.0 ml
(B) 72 ml
(C) 70.2 ml
(D) 71.2 ml
(E) 70.0 ml

Answer 1

To solve this question we will be finding the significant figures of the least precise term out of 50.0 ml and 22ml. then we can easily find the resulting volume of water in the beaker.

Complete Solution :
- We have been provided with 22 ml of water in a beaker,
- Now according to the question, we need to find out total volume of water present in the beaker in the beaker if we add 50.0 ml of water to this beaker,
- So, if we would add 50.0 ml of water add 50.0 ml of water to a beaker containing 22 ml of water, then total water in the beaker would come out to be:
50.0 ml + 22 ml = 72 ml
So, there would be 72 ml of water in the beaker.
- The volume of water would not contain any decimal point after 72 because 50.0 ml has one decimal point and 22 ml has 0 decimal point.
- The answer or result of addition must contain the same number of significant figures.
- We know that the significant figures are the number of digits in a value, that contribute to the degree of accuracy of the value, and we would consider the significant figures of the least number.
So, that’s why the final volume would be 72 ml.
So, the correct answer is “Option B”.

Note: for determining significant figures we need to follow certain rules:

1. non-zero digits are always considered as significant.
2. any zero between two significant figures will be considered as significant.
3. zero in the decimal portion is only significant.