Problem 52P

Perform each conversion.

(a) 45.6 J to calories

(b) 355 cal to joules

(c) 43.8 kJ to calories

(d) 215 cal to kilojoules

Solution 52P

Here, we are going to convert the unit from Cal to joule or Joule to cal.

(a) 45.6 J to calories

We know,

1 Cal = 4.1868 Joule

Therefore, the conversion factor =

Thus,

45.6 J x = 10.89 cal

Therefore, 45.6 J = 10.89 cal

(b) 355 cal to joules

We know,

1 Cal = 4.1868 Joule

Therefore, the conversion factor =

Thus,

355 cal x = 1486.31 Joule

And, 1000 kJ = 1 J

Therefore,

355 cal = 1486.31 Joule = 1.486 kJ

(c) 43.8 kJ to calories

We know,

1 Cal = 4.1868 Joule

1000 J = 1 kJ

Therefore, the conversion factor = ,

Thus,

43.8 kJ x x = 10461.45 cal

Therefor

And, 1000 calories = 1 kilocalories

134 kJ = 10461.45 cal = 10.461 kilocalories

(d) 215 cal to kilojoules

We know,

1 Cal = 4.1868 Joule

1000 J = 1 kJ

Therefore, the conversion factor = ,

Thus,

215 cal x x = 0.90 kilojoules