General Chemistry Answers

What happened to the number of moles in a sample that originally occupied

500mL with 3.50 moles and then occupied 700 ml?

how many formula units of iron (III) oxide can be produced from the reaction of 108 g of iron with 72.1 L of oxygen gas at STP?

how many formula units of iron (III) oxide can be produced from the reaction of 108 g of iron with 72.1 L of oxygen gas at STP?

For each redox reaction below, determine the oxidation number of each element present. Write your answer above each symbol for the element.

a. 2Sb(s) + 3I2(g) —> 2SbI3(s)

b. 2Cu2S(s) + 3O2(g) —> 2Cu2O(s) + 2SO2(g)

c. PbO2(s) + Pb(s) + 2H2SO4(aq) —> 2PbSO4(aq) + 2H2O(l)

d. NH4NO3(s) —> 2H2O(g) + N2O(g)

e. Fe2O3(s) + 3CO(g) —> 2Fe(s) + 3CO2(g)

Calculate the standard cell potential for

Zn(s) + Ag*(aa) → Zn²+ + Ag(s)

Assume that all the concentrations are 1.0 M. Standard reduction potentials are given in table 1.

Write half-reactions for each of the following redox reactions. Identify each half-reaction as being either oxidation or reduction. Show your work.

A. SnS2(s) + O2(g) —> SnO2(s) + SO2(g)

B. Mg(s) + N2(g) —> Mg3N2(s)

Balance the following equations, using the oxidization number method for the redox part of the equation. Show your work.

A. Cu2O(s) + H2(g) —> Cu(s) + H2O(l)

B. Cl2(g) + KBr(aq) —> Br2(l) + KCl(aq)

What is the pH of a 1.5x10^-3 M solution of NaOH, a strong base? Show your work.

1.)calculate the volume of 0.400M H3PO4 needed to react with 200.0mL of 0.200 M NaOH

____H3PO4 (aq) +___NaOH(aq) -____Na3PO4(aq) +___H2O(l)

1.)calculate the volume, in mL of 1.72M HCl solution that will react with 2.67 mol of CaCO3? (Ans. 3.10x103mL

___HCl+___CaCO3____CaCl2+___H2O+__CO2

2.)If 0.650% solution of NaCO3 will be used to precipitate Ca+2 from solution, determine the amount of solution, in grams, needed to precipitate 5.00x102mL of 0.01120M Ca+2?(Atomic mass :Na=22.99g/mol:C=12.01g/mol:O=16.00g/mol:Ca=40.08g/mol:Ans.91.3g)

____Na2CO3(aq)+___Ca+2(aq)____CaCO3(s)+___Na+(aq)