auizfchemra serine zorz Name K E Y
Each question is worth 5 points, totaling 40 points for 8 questions.
Avogadro's number is 5.022 x L023.
1.) Write the balanced chemical equation for the combustion reaction when CsHs is burned in air.
Cal+Ct0o-(3)* Scozgl r- 4A.c,r,
2.) What is the formula weight of theobromine, CTHsNaO2 , found in chocolate?
FrD = +(rir' itil'* s,(,:,,;;;i.il ii(rt ota*"t)na (rc,*V
= 180. l+ 3{*l
3.) What is the percent by mass of nitrogen in theobromine?
4
4.) How many molecules in 1.530 grams of theobromine? o z ,/7 /l
t,soyx W^x *
5.) What is the empirical formula of a compound that is 40.00 %o carbon by mass, 6.70% hydrogen
by mass and 53.3Q % oxygen by mass?
4o,ffitC ; W*^'*'i.iEl^'&-:C --> t c
'f u',u 8
(o3o"qRx Wu = b.WT,^"%ail -? l,q?{ H+P
53,30\oy t4: >
d tr- doa
AW)x DDo6 = 3l,to?o
180,1+
= 5 lt,l xt}al
4u&*-ZA
\b,fl$
