I need help again.. Again, serious answers only please?

Question

Thanks in advance. I'll award 10 pts to whoever gets it right first!!


How many milliliters of 0.150 M NaOH is needed to react completely with 3.45 g iodine according to the equation:

3 I2 + 6NaOH --> 5NaI + NaIO3 + 3H2O?


How many grams of oxygen are needed to burn 56.92 g of C10H22


Hydrazine, N2H4, is an important industrial reagent. It is synthesized by the Raschig process.

2NaOH(aq) + Cl2(g) + 2NH3(aq) --> N2H4(l) + 2NaCl(aq) + 2H2O(aq)

If you combine 100. g each of NaOH, Cl2, and NH3 and the reaction is complete, which reactant(s) will be left over?

1. NaOH 2. Cl2 3. NH3

a. 1 only
b. 2 only
c. 3 only
d. 1 and 2 only
e. 2 and 3 only

oh, and i need help with this one too. Please help me!

Phosphoric acid is made from phosphate rock, one form of which is apatite, Ca5(PO4)3F (molar mass = 504.3 g/mol).

Ca5(PO4)3F(s) + 5H2SO4(aq) --> 5CaSO4(s) + 3H3PO4(aq) + HF(aq)

If you use 100. g of apatite and 500. g of sulfuric acid (molar mass = 98.07 g/mol), how many grams of phosphoric acid (97.99 g/mol) can be produced?

Answer 1

QUE 1.
MM I2 = 253.8 g/mol
mole NaOH = 3.45 g I2(1mol/253.8g)I2*(6molesNaOH/3molesI2)
= 0.0272 mole NaOH
Volume of NaOH = 0.0272/0.15mole/L = 0.18133 L
= 181.33 mL NaOH

QUE 2
C10H22 + (31/2)O2 ---> 10CO2 + 11 H2O
MM C10H22 = 142.176 g/mol
56.92g(1mol/142.176)(15.5 molO2/1molC10H22)(32g /1mol)O2
= 198.57 g of O2

QUE 3
get the limiting reactant
moles of N2H4 from NaOH =
100g NaOH(1mol/40g)NaOH*(1mol N2H4/ 2mol NaOH)
= 1.25 moles N2H4
moles of N2H4 from Cl2 =
100g Cl2(1mol/70.9g)Cl2*(1mol N2H4/ 1mol Cl2)
= 1.41 moles N2H4
moles of N2H4 from NH3 =
100g NH3(1mol/17.031g)NH3*(1mol N2H4/ 2mol NH3)
= 2.94 moles N2H4

therefore the excess reagent are NH3 and Cl2
thus the answer is E...

best answer?

Answer 2

NaOH, Cl2, NH3 question, answr is b, since you need 2 times more for NaOh and NH3, the ratio is 2:1:2, so if you assume that both NaOH and Nh3 consume 100 grams then Cl2 only uses up half.

Answer 3

For the multiple choice question, the answer is d. You have to look at molar ratios. Cl2, as the heaviest, has the least amount of moles, making it the limiting reagent in the reaction. The other two don't really react with each other leaving them left over.

Answer 4

Forget the 10 points, I'll settle for the two points.

Thanks.

Answer 5

oh my god!!! i have been out of school for 20 years we never done nothing like this in chemistry.

Answer 6

181ml
199g
e.
58.2g

Answer 7

whoa, complicated!!