Chemistry related

Question

A student determines the mass of an object using a triple beam balance which is sensitive to 0.01 g. When the beam balances, the rider on one beam is in the notch marked 60 g, the rider on another beam in the notch marked 7 g, and the rider on the third beam, which is graduated by hundredths of a gram, is at zero. Considering significant figures, what mass should be recorded?

(A)67.0 g

(B)76.0 g

(C)67.00 g

(D) 76.000 g

(E) 67.000 g

could you explain why you got that answer

Answer 1

For a triple beam balance, you add up the three values ad account for significant figures for the smallest one. In this case we have

** 60g

** 7g

** 0.00g

The last one is the part to be careful on. The problem just says it reads zero, but right before that it says that beam reads in hundredths. That means our zero is zero to the hundredth's place. If we had a more accurate scale that read to thousandths, it would have been 0.000g to show that thousandths place.

Now that we have the three values we add them up to get 67.00g