Question

71. If a gas furnace releases 450 kcal of heat energy, what is the energy in kilojoules? 11 cal = 4.184 J

For determining the significance digits for answer do we determine the given value to determine how Many sig figs are for the answer

Or

Do we determine all parts of the equation, such as, the conversions or

Can someone please go in depth

Answer 1

Given that gas furnace releases 450 kcal of heat energy.

We have to convert energy into kilojoules from kilocalories.

We know that 1 cal = 4.184 J

450 kcal = 450 x10³ cal = 450 x10³ x 4.184 J = 1882.8 x10³ J = 1882.2 kJ

No need to give significant figures for the energy value.

If you are interested to know the number of significant figures in the energy value above, see the below part.

Significant figures in 1882.8 x10³ J is 7.

Significant figures indicate the number of important single digits in the coefficient of an expression.