Adding Another Dimension to Dimensional Analysis A serious deficiency among college students is their general lack of eommunieation ahility. Mandatory use of dimensional analysis can be a help because working problems in a clear and concise way utilizing dimensional analysis is a form of effective communication. However, a simple unit is not always enough. For example, i t is more effective to identify substances when using units of quantity (27 moles of HCI rather than just 27 moles). Sometimes adding a few extra words further improves the situation.
Typical ( 3 W ( 2 g) Approach 1cal of heat absorbed %g,",","i (3 OC temp incr in 2 g H20) 1 "C temp iner in 1g Hz0
zg$&h
(75 g)(10%)= 7.5 g
10 grams of salt Suggested (75 grams of sample) Approach (100 grams of Approach 1063 "C
+ 273 = 1336 'K
Suggested (1063 oC) Approach 1 "C temp incr
Fp;ich
MW of COz = 12
"ggested MW of Approach
= 7.5 g salt
)+
273 "K = 1336 'K
+ 2(16) = 44 amu
12 amu con= (1 c atom) (Catom) + 2 0 atoms
Middle Georgia College Coehran, GA 31014
302 1 Journal of Chemical Education
Ronald DeLorenzo
