Chemistry FR

Test Preparation AP Test Preparation
141

<p>I put 0 mol...wasnt thinking about fraction coeffiecients...durrrr</p>

142

<p>I put half mole~</p>

143

<p>well with the spectator ions it would be</p>

<p>2NaOH + Pb(NO3)2 --> Pb(OH)2 + 2NaNO3</p>

<p>so i said 1 mol Pb(OH)2 and 2 mol NaNO3</p>

<p>who knows, could be wrong</p>

144

<p>Cant look at the coefficients, you only had 1 mol of NaOH, not enough reactant to make the products told from the equation</p>

145

<p>what was the sign of Evolt for galvanic cell question?
and can someone answer my q about the expression for 5MV ?
if we could just explain how to find grams and mol instead of
actual expressions ??? thanks</p>

146

<p>The sign of Evolt was negative so the sign of gibbs is positive, if i remember correctly</p>

147

<p>The sign of Evol was negative.</p>

148

<p>As long as you were describing the right equation you should be fine.</p>

149

<p>Reactions:</p>

<p>Pb2+ + 2OH- ---> Pb(OH)2
1/2 mole of product forms, since you only have 1/2 the OH- required to react with all the Pb2+</p>

<p>H+ + CaCo3 ----> Ca2+ + CO2 + H20
acid rain</p>

<p>Ag+ + Fe2+ ---> Ag(s) + Fe3+
solid silver</p>

150

<p>"2HNO3 + CaCO3 --> H2CO3 + Ca2+ + 2NO3-"
Nope- CO32- is a base, so it's an acid-base reaction.</p>

151

<p>Wow i got a lot of these right! Anyone else thought that the multiple choice was a torture?</p>

152

<p>yeah MC was a LOT harder than FR ... definitely a torture lol</p>

153

<p>fhqwgads' reactions are right except for missing a 2 in front of H+</p>

154

<p>wait i thought it would produced carbonic acid, which dissolves limestone. It produces CO2 and H2O? why?</p>

155

<p>That's what I put too. Limestone breaks down and CO2 and H2O are produced.</p>

156

<p>2H+ + CaCO3 -> CO2 + H2O + Ca+2</p>

<p>The Equations were horribly easy this year.
I was really scared for the free response, but to make up for losing choices, they just made the entire thing easier.</p>

<p>But I didn't get the resonance forms for SO2. I was wondering why the box was so big!</p>

157

<p>someone should compile all the answers and post it in one post so its easier to see =)</p>

158

<p>Will I get no points if i wrote 2H+ + CaCO3 ------> H2CO3 + Ca2+</p>

159

<p>I think you'll be able to get the Reactants, Balancing, and Explanation Points.</p>

<p>I was stupid and I was thinking acid rain, but I don't remember if I actually wrote Acid Rain for this... :(</p>

160

<p>you will get 1 point for products..and 1 more if you answer the question right which was easy anyway</p>