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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: IceRiceIce on August 02, 2020, 06:21:58 PM

Title: Metric Conversions
Post by: IceRiceIce on August 02, 2020, 06:21:58 PM
For homework I got over summer there is one part that I just don't get. I know how to do metric conversions but my teacher wants me to do calculations including units that aren't in the same category. For example (100g)/(15mL),
       (41.7kg) / (1.3 dm * 3.4 dm * 2.1 dm),    1400J/ (45 g) (37 C)     How do I do these questions and what are the answers?
Title: Re: Metric Conversions
Post by: blakeb on August 02, 2020, 10:32:28 PM
For these questions, you get what's known as derived units, or the combination of different metric units. That "1400J/ (45g)(37 C)" problem is involving the unit for specific heat. For that problem in particular, you would solve the problem normally algebraically, then express the derived unit as "J/g C."

Another way of thinking about it is thinking about meters per second or miles per hour. You can't divide a distance by a duration and get a simple unit; You get a derived unit. There are exceptions to this rule, for instance a Joule is a name for the common derived unit of kg·m2/s2 expressing a unit of energy. This is common in physics and chemistry for expressing common derived units.
Title: Re: Metric Conversions
Post by: Borek on August 03, 2020, 03:18:01 AM
For homework I got over summer there is one part that I just don't get. I know how to do metric conversions but my teacher wants me to do calculations including units that aren't in the same category. For example (100g)/(15mL),
       (41.7kg) / (1.3 dm * 3.4 dm * 2.1 dm),    1400J/ (45 g) (37 C)     How do I do these questions and what are the answers?

Can you quote the entire problem? These are not questions, these are just bunches of numbers.