# Chemistry

P4O10(s) + 6 H2SO4(l) --> 4 H3PO4(aq) + 6 SO3(g)

Pure H2SO4(l) has a density of 1.84 g/mL. If 45.0 mL of H2SO4(l) reacts:

What mass of P4O10 reacts?

- it's given 45.0 mL of H2SO4 with the density of 1.84 g/mL, so the mass of H2SO4 is 45*1.84 = 82.8 (g) so converts to 0.845 moles of H2SO4
- the ratio between P4O10 and H2SO4 is 1 : 6, so the moles of P4O10 reacting is 0.141
so the mass of P4O10 reacts is 0.141*284 = 40.044 (g)

What volume of SO3(g) at STP is produced?

- the ratio between H2SO4 and SO3 is 1 : 1, so the moles of SO3 produced is 0.845
so the volume of P4O10 produced is 0.845*22.4 = 18.928 (L) in STP

A 200. mL sample of H3PO4 is titrated with 56.2 mL of 0.700M NaOH.
2 NaOH(s) + H3PO4(l) --> Na2HPO4(s) + 2H2O(l)

a) What is the molar concentration of H3PO4?

it's given 56.2 mL of 0.700M NaOH, so converts to 56.2/1000*0.7 = 0.04 moles of NaOH
- the ratio between NaOH and H3PO4 is 2 : 1, so the moles of H3PO4 needed is 0.02
- 0.02 moles H3PO4 in a 200 mL sample of H3PO4, that means the molar concentration of H3PO4 is 0.02/(200/1000) = 0.1(moles/L)

b) How many moles of Na2HPO4 are produced? (2 marks)

- the ratio between NaOH and Na2HPO4 is 2 : 1, so the moles of Na2HPO4 produced is 0.02

1. 👍 0
2. 👎 0
3. 👁 117
1. Looks good to me, except for 2B. Double check that one. The moles of H3PO4 are proportional to its conjugate base.

1. 👍 0
2. 👎 0
2. Nevermind. That one is correct as well.

1. 👍 0
2. 👎 0
3. Thank you !

1. 👍 0
2. 👎 0
4. H3PO4/H2SO4 problem is OK>
For M H3PO4 I get 0.098M
For mols Na2HPO4 I get 0.0196

1. 👍 0
2. 👎 0
posted by DrBob222

## Similar Questions

1. ### chemistry

P4O10(s) + 6 H2SO4(l)  4 H3PO4(aq) + 6 SO3(g) Pure H2SO4(l) has a density of 1.84 g/mL. If 45.0 mL of H2SO4(l) reacts: What mass of P4O10 reacts? 45.0 mL X 1.84 g/mL X (1 mol/98.1 g) = 0.844 mol H2SO4 Moles P4O10 = 0.844 mol

asked by Shine bright shine far on March 5, 2019
2. ### Chemistry and @DrBob222

Sorry for the mix up -- here's what DrBob222 posted for the Chm or Chemistry question: What subject is CHR? If you don't label the subjects correctly the proper tutor won't know you need help. This question can't be answered as

asked by Writeacher on September 4, 2017
3. ### Chemistry

SO3 + H2O = H2SO4 If you react 34 g of water and have excess SO3, how much H2SO4 would you theoretically produce?

asked by Anonymous on March 15, 2011
4. ### Chemistry

SO3 + H2O = H2SO4 If you react 34 g of water and have excess SO3, how much H2SO4 would you theoretically produce

asked by Chrissy on March 15, 2011
5. ### Chemistry

Consider 18.0 M H2SO4, if you need to make 250.0 mL of a 3.0 M solution of H2SO4, how would you do this? 18.0 M H2SO4 has a density of 1.84g/mL what is the molality of solution? Mass % of H2SO4 in the solution and the mol fraction

asked by Marie on April 30, 2013
6. ### chemistry

Consider 18.0 M H2SO4, if you need to make 250.0 mL of a 3.0 M solution of H2SO4, how would you do this? 18.0 M H2SO4 has a density of 1.84g/mL what is the molality of solution? Mass % of H2SO4 in the solution and the mol fraction

asked by Marie on April 29, 2013
7. ### chemistry

a sample of sulphuric acid is 95.7% by mass and has a density of 1.84g/cubic cm.calculate the mass of pure H2SO4 in a 2.00L bottle and volume of acid that contain 200g of pure H2SO4.

asked by grace on January 26, 2013
8. ### Chemistry

If the percent yeild of the following equation is 55%, how many grams of H2SO4 are produced when 4.88 x 10^24 molecules of SO3 are combined with excess water? SO3(g)+H2O(l)->H2SO4(aq). what would be the formula to solve this

asked by Sean on April 10, 2016
9. ### chemistry (Pls Bob check for me)

A 0.5g of fuming h2so4 oleum is diluted with water. This solution is completedly neutralized by 26.7ml of 0.4N naoh. Find the percentage of free so3 in the sample The asnwer 20.6% My calculation h2so4= 98/2 = 49 so3= 80/2 = 40

asked by Fai on March 24, 2013
10. ### Chemistry

If the standard state of sufur is S8 (s), which of the following equations represents the standard enthalpy of formation of H2SO4 (ℓ) ?  A. 2H (g) + S (g) + 4 O (g)  H2SO4 (ℓ) B. H2 (g) + S8 (g) + 2 O2 (g)  H2SO4(ℓ)

asked by Hannah on October 2, 2011

More Similar Questions