Expressing amounts of energy in different energy units is necessary to solve many chemistry problems. For practice, complete the following table. FILL IN THE BLANKS PLEASE.
The Joule (J) is the SI unit of energy. 1 calorie (cal) = 4.184 J
J cal kJ
695 ___ ___
___ 132 ___
___ ___ 0.478
1 cal = 4.184 J
1000 J = 1 kJ.
The way you do these is to make the units convert from what you have to what you want. I wrote the factors above. Here is how you do the first one. I'll leave the others for you.
The factor for calories to J is one of these two; i.e., 1 cal/4.184 J OR 4.184 J/1 cal. You want to convert 695 cal to J.
695 cal x factor = ? J and you must plug in the factor. It MUST be one of the two above. Let's try one factor, then the other.
695 cal x (1 cal/4.184 J) = ? and
695 cal x (4.184 J/1 cal) = ?
ONE of those MUST be right. Which one. Take them 1 at a time. Only look at the units.
The first one is cal x cal/J which gives (cal^2/J). You were looking for J. Right? So this one can't be right. Look at the second.
Again, look only at the units.
The second one is cal x J/cal. Notice that cal cancels and J doesn't so that's the one to use because you want J. Therefore,
695 cal x (4.184 J/cal) = ? J and that just leaves the calculation. If you want to put that into a formula, it is this.
(#+unit you have) x (unit you want/unit you have) = #+unit you want to convert to.
I'll be glad to check your work on the others.
To fill in the blanks, we can use the conversion factor that 1 calorie (cal) is equal to 4.184 joules (J). We can also convert between kilojoules (kJ) and joules (J) by multiplying or dividing by 1000.
Using this information, we can complete the table:
J cal kJ
695 ___ ___
To convert 695 joules (J) to calories (cal), we divide by the conversion factor:
695 J / 4.184 J/cal = 166.21 cal
So, the blank is 166.21.
___ 132 ___
To convert 132 calories (cal) to joules (J), we multiply by the conversion factor:
132 cal * 4.184 J/cal = 551.088 J
So, the blank is 551.088.
___ ___ 0.478
To convert 0.478 kilojoules (kJ) to joules (J), we multiply by the conversion factor:
0.478 kJ * 1000 J/kJ = 478 J
So, the blank is 478.
The completed table is as follows:
J cal kJ
695 166.21 ___
___ 132 551.088
___ ___ 0.478
To complete the table, we can use the conversion factor that 1 calorie is equal to 4.184 Joules. Let's fill in the blanks step by step:
1. For the first row, we've been given the value in Joules: 695 J. We need to find the equivalent value in calories and kilojoules.
To convert from Joules to calories, we divide the value in Joules by the conversion factor:
695 J ÷ 4.184 J/cal ≈ 166 cal.
To convert from Joules to kilojoules, we divide the value in Joules by 1000 (since there are 1000 Joules in 1 kilojoule):
695 J ÷ 1000 kJ/J = 0.695 kJ.
Therefore, the completed first row is:
695 J cal kJ
695 cal 166 0.695
2. For the second row, we've been given the value in calories: 132 cal. We need to find the equivalent value in Joules and kilojoules.
To convert from calories to Joules, we multiply the value in calories by the conversion factor:
132 cal × 4.184 J/cal ≈ 552 J.
To convert from calories to kilojoules, we multiply the value in calories by the conversion factor and divide by 1000:
132 cal × 4.184 J/cal ÷ 1000 kJ/J ≈ 0.552 kJ.
Therefore, the completed second row is:
132 J cal kJ
552 cal 132 0.552
3. For the third row, we've been given the value in kilojoules: 0.478 kJ. We need to find the equivalent value in Joules and calories.
To convert from kilojoules to Joules, we multiply the value in kilojoules by 1000:
0.478 kJ × 1000 J/kJ = 478 J.
To convert from kilojoules to calories, we multiply the value in kilojoules by the conversion factor and divide by 4.184:
0.478 kJ × 4.184 J/cal ≈ 2.000 cal.
Therefore, the completed third row is:
478 J cal kJ
478 cal 132 0.478
By using the conversion factors and applying the appropriate conversions, we can now express the given values in different energy units.