This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: South Pasadena 0 AP Chemistry Name
Period _ Date / j 6 o__ Energy and Chemical Reactions ——_ CALORIMETRY Measuring heat (formerly measured in calories) is called calorimetry. Now we measure heat energy in
Joules (J). The equation we use is: q = heat energy
m = mass of water C = the specific heat capacity
AT = the change in temperature (in °C or K) q = m°CAT 1. Water has a speciﬁc heat capacity of 4.184 J/g°C.
This means it takes 4.184 J to heat 1.00 gram of water 100°C. a) How much energy will it take to heat 10.0 grams of water 1°C? 40 at! J‘
b) How much energy is needed to heat 30.0 g H20 from 10.0 °C to 50.0 °C‘? 5 O '20 ﬂ ;5 GB:— éODg) (4454251.) (qop’cﬁ = @5020? 2. Let’s try a standard calorimetry problem. A pot of water (2.5 Liters of water) initially at 250°C is heated to boiling (100°C). ZngMy ii.
How much energy (in J) is needed to heat the water? (The density of water is 1 g/mL.) l L‘ I“ : wag
3:.Lzsaog) Largest meow =l78‘t5 ooa' —— 75000on What would this amount of heat be in k]? 7 3:" S U 3"" \ 7 5’0 in: i 2' 8“" P13“: ' 3. What amount of heat is released when 175 g of water cools from 100°C to room temperature, 20.0 °C?
‘8'“ (1153 )L‘tm 3' >630, we) r — 585% 3‘ = 591: L3 5 ... _ e
65:40— wuzaa lmu" is 6cm app, 4. We don’t always have to warm up or cool down water. The speciﬁc heat capacity of copper metal is
0.39 .l/g‘°C. It is :45 i e;— (tagger/Mt) to heat up copper than to heat up water. How much energy would it take to heat up a 5.20 g sample of copper from 20.0 0C to 100°C? %:(§'ZOJ>( ' 5‘1 ‘3 )(3’0. “(3 :: Hal. 2H3 . 11903", J 5. If 300. J of heat energy were used to heat up a 5.00 gram sample of copper metal and a 5.00 ram
Sample of water both starting at 100°C, calculate the final temperature of each sample?®
L. 3,»..ch ileCOT 3003 : gooQCe‘l S 7." 3003': 6°03) (4151;; 1;,
0 6‘ 131°10ng°°> ; 19;" 11..“L3002 _;_ W2).
cameo m tS«JGtte~z) ...
View
Full Document
 Spring '11
 HACES
 Calorimetry, AP Chemistry

Click to edit the document details