Suppose you are asked to find 91,321,972×0.007004. doing a quick estimate by rounding the numbers in scientific notation, what value would you expect the answer to be close to? (if you need a review of the estimation technique, watch the video scientific notation, part 4.)

we need to estimate the product of two numbers by writing them in scientific notation and rounding them off.

In scientific notation, number 91321972 can be written as

If we round this off to 1 significant figure, it would be:

In scientific notation, number 0.007004 can be written as

If we round this off to 1 significant figure, it would be:

Product of these two numbers:

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.