Friday
December 19, 2014

Homework Help: Chemistry

Posted by Kara on Sunday, March 27, 2011 at 11:45pm.

In the classroom, we reacted
Mg(s) + 2HCl -> MgCl2(aq) + H2 (g)
(0.31 g of Mg(s), and 99.46 g of HCl)
Initial temp. = 22.5 celsius, max. temp. 36.0 celsius

and

MgO(s) + 2HCl -> MgCl2(aq) + H2(g)
(1.00 g of MgO(s) and 97.71 g of HCl)
Initial temp. 22.0 celsius, max. temp. 28.5 celsius.

Please note that the temperatures were crudely taken, so a wide range of experimental error is likely.

When calculating the deltaH for the first equation, this is what I got

Q=mcDeltaT
Q=(99.46)(4.18)(13.5)
Q=5612.5 J
Q=5.6 kJ

and the second reaction;

Q=mcDeltaT
Q=(97.71)(4.18)(6.5)
Q=2654 J
Q=2.7 kJ

My question is, how do those numbers make any sense? Or am I just confused as to what those numbers represent? Thanks in advance!

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Chemistry - Find the enthalpy of combustion of magnesium using Hess' law given ...
Chemistry - For the equation q=cΔt, q=100KJ, initial temp=20 degrees ...
Socials - Temperature decreases approximately 1degree Celsius for each 150 ...
Chemistry - How many mole of H2 will be produced if 0.500 grams of magnesium is ...
Biology - Hey I am doing a lab, the link is down h t t p : //w w w . sd67 . bc...
Chemistry - Mg(s) + 2HCl(aq) --> MgCl2(aq) + H2(g) If 1.0g of Mg is reacted ...
Chem - If it takes 600 calories of heat to raise 75ml of water to a final temp ...
CHEMISTRY HELP !!!! - Cell Designation : E (measured) = Sn I Sn^2+ II Cu^2+ I ...
Chemistry - If Chelcy and Allyson reacted 2.55 grams of Mg with excess ...
chemistry - A mixture of CaCO3 and MgCO3 weighing 7.85 g was reacted with excess...

Search
Members