85 !
1.) 2hgo(s) --> 2hg(l) + o2 (g)
in a certain reaction 8.74 g of hgo is decomposed, producing 6.42 g of hg. what is the percent yield for the reaction?
2.) fluorine gas reacts with a solution of sodium bromide in a single-replacement reaction producing aqueous sodium fluoride and bromine gas.
if a reaction starts with 0.240 mol fluorine gas, how many moles of sodium fluoride are produced?
3.) 4 fe(s) + 3o2(g) --> 2fe2o3(g)
in a certain reaction, 54.6 g of iron is reacted with 91.6 g of oxygen
how many grams of iron (iii) oxide are produced in the reaction?
4.) ga2o3(s) + 3socl2(l) --> 2gacl3(s) +3so2
in a certain reaction, 71.8 g of ga2o3 is reacted with 110.8 g socl2.the gacl3 produced is collected and its mass founded to be 97.66 g.
what is the theoretical yield of gacl3?
5.) n2 (g) + 3h2 (g) --> 2 nh3 (g)
the equation above is the equation for the haber process.
in a certain reaction, you start with 6.0 moles of nitrogen and 10.0 moles of hydrogen,
which is the excess reactant?
6.) b2o3(s) + 3c(s) + 3cl2 (g) > 2 bcl3(g) + 3co(g)
what is the mass of carbon required in order to produce 3.00 mol bcl3?
7.) b2o3(s) + 3c(s) + 3cl2 (g) > 2 bcl3(g) + 3co(g)
calculate how many moles of bcl3 are produced from the reaction of 122.0g of b203?
8.) 4 fe(s) + 3o2(g) --> 2fe2o3(g)
in a certain reaction, 54.6 g of iron is reacted with 91.6 g of oxygen
how many grams of the excess reactant remain after the reaction is complete?
9.) 2no(g) + o2 (g) --> 2no2
how many grams of no are required to react fully with 2.50 mol of o2?
10.) n2 (g) + 3h2 (g) --> 2 nh3 (g)
the equation above is the equation for the haber process.
in a certain reaction, you start with 3.0 moles of nitrogen and 5.0 moles of hydrogen, which molecule is the limiting reagent?
11.) 2hgo(s) --> 2hg(l) + o2 (g)
in a certain reaction 8.74 g of hgo is decomposed, producing 6.42 g of hg.
what is the theoretical yield of hg?
12.) b2o3(s) + 3c(s) + 3cl2 (g) > 2 bcl3(g) + 3co(g)
how many moles of chlorine are used up in a reaction that produced 175 g of bcl3?
13.) 4 fe(s) + 3o2(g) --> 2fe2o3(g)
in a certain reaction, 54.6 g of iron is reacted with 91.6 g of oxygen
what is the limiting reactant?
14.) n2 (g) + 3h2 (g) --> 2 nh3 (g)
the equation above is the equation for the haber process.
in a certain reaction, you start with 6.0 moles of nitrogen and 10.0 moles of hydrogen. how many moles of ammonia will be produced in the reaction?
15.) b2o3(s) + 3c(s) + 3cl2 (g) > 2 bcl3(g) + 3co(g)
how many moles of carbon are used up in a reaction that produced 0.70 kg of bcl3?
16.) fe2o3(s)+3co(g)⟶2fe(s)+3co2(g)
a certain reaction produced 7.40 mol carbon dioxide. how many moles of both fe2o3 and co reacted?

1)    2 HgO    →      2 Hg + O₂

 (2 x 216.59 g) → gives → (2 x 200.59 g)

  433.18 g   → gives → 401.18 g

    8.74 g     → gives → ? g

by cross multiplication:

Theoretical yield = (401.18 x 8.74) / 433.18 = 8.094 g

% yield = (actual yield / theoretical yield) * 100

            = (6.42 / 8.09) * 100 = 79.3 % 

2) F₂ + 2 NaBr → 2 NaF + Br₂

1 mole F₂ → gives → 2 moles NaF

0.24 mol F₂ will give ?? mol NaF

= (0.24 x 2) / 1 = 0.48 mol NaF

3) 4 Fe(s) + 3 O₂(g) → 2 Fe₂O₃(s)

number of moles of Fe = (54.6 / 55.845) = 0.97 mol

number of moles of O₂ = (91.6 g / 32) = 2.8625 mol

4 moles Fe react with 3 moles O₂

0.97 mol Fe will react completely with 0.7275 mol O₂

so 0.97 mol Fe is the limiting reactant and O₂ present in excess

4 moles Fe(s)    → gives → 2 moles Fe₂O₃  

0.97 mol Fe(s)  → gives → ? moles Fe₂O₃

= (0.97 x 2) / 4 = 0.485 mol Fe₂O₃

mass of Fe₂O₃ = 0.485 mol * 159.69 g/mol = 77.45 g

4) Ga₂O₃(s) + 3 SOCl₂(l) → 2 GaCl₃(s) + 3 SO₂

Molar mass of Ga₂O₃ = 187.44 g/mol

Molar mass of SOCl₂ = 118.97 g/mol

Mass of Ga₂O₃ = 71.8 g 

Mass of SOCl₂ = 110.8 g 

number of moles = mass (g) / molar mass 

number of moles of Ga₂O₃ = 71.8 / 187.44 = 0.38 mol

number of moles of SOCl₂ = 110.8 / 118.97 = 0.93 mol

1 mole Ga₂O₃(s) react with 3 moles SOCl₂

0.38 mol Ga₂O₃ react with 1.14 mole SOCl₂

But only 0.93 mol SOCl₂ present so it is the limiting reactant

3 moles of SOCl₂ → gives → 2 moles GaCl₃

0.93 mol SOCl₂  → gives → ? mole GaCl₃

= (2 x 0.93) / 3 = 0.62 mole

Mass of GaCl₃ = 0.62 * 176.073 = 109.16 g

5) N₂(g) + 3 H₂(g) → 2 NH₃(g)

  1 mol N₂ reacts with 3 moles H₂

 so 6 moles N₂ will react completely with 18 moles H₂

But moles of H₂ present is only 10 moles, so Nitrogen is considered as the excess reactant.

6) B₂O₃(s) + 3 C(s) + 3 Cl₂(g)   → 2 BCl₃(g) + 3 CO(g)

3 moles C → gives → 2 moles BCl₃

? moles C → gives → 3 moles BCl₃

 moles of C = (3*3) / 2 = 4.5 moles C

Mass of carbon required = 4.5 moles * 12 g/mol = 54 g carbon

7) B₂O₃(s) + 3 C(s) + 3 Cl₂(g) → 2 BCl₃(g) + 3 CO(g)

number of moles of B₂O₃ =  mass / molar mass

                                      = 122 g / 69.6182 = 1.75 moles 

1 mole B₂O₃       → gives → 2 moles BCl₃

1.75 mole B₂O₃  → gives → ? moles BCl₃

= 2 * 1.75 = 3.5 moles BCl₃ 

8) 4 Fe(s) + 3 O₂ → 2 Fe₂O₃

moles of Fe = (54.6 g) / (55.845 g/mol) = 0.98 mol

moles of O₂ = (91.6 g) / (32 g/mol) = 2.8625 mol

4 moles Fe(s) react with 3 moles O₂(g)

0.98 mol Fe(s) react completely with ? moles O₂(g)

= 0.735 mol O₂

moles of excess oxygen = 2.8625 - 0.735 = 2.1275 mol 

mass of excess oxygen = 2.1275 * 32 = 68.08 g O₂

9) 2 NO(g) + O₂(g) → 2 NO₂ 

2 moles NO react with 1 mol O₂

? moles NO will react with 2.5 mol of O₂

= (2 * 2.5) / 1 = 5 moles NO

Mass of NO = 5 * 30 = 150 g

10) N₂(g) + 3 H₂(g) → 2 NH₃(g)

1 mole N₂ reacts with 3 moles H₂

so 3 moles of N₂ will react completely with 9 moles H₂

but only 5 moles of Hydrogen present so it is the limiting reactant

11) 2 HgO(s)        →      2 Hg(l) + O₂(g)

(2 x 216.59 g) give    (2 x 200.59)

433.18 g will give    401.18 g

8.74 g HgO  will give ? g Hg

Theoretical yield of Hg = (8.74 x 401.18) / 433.18 = 8.094 g

12) B₂O₃(s) + 3 C(s) + 3 Cl₂(g) → 2BCl₃(g) + 3 CO(g)

number of moles of BCl₃ produced = 175 g / 117.17 g/mol = 1.5 moles

3 moles of Cl₂ produce 2 moles BCl₃

? moles of Cl₂ produces 1.5 mole BCl₃

= (1.5 x 3) / 2 = 2.25 moles Cl₂

13) 4 Fe(s) + 3 O₂ → 2 Fe₂O₃

moles of Fe = (54.6 g) / (55.845 g/mol) = 0.98 mol

moles of O₂ = (91.6 g) / (32 g/mol) = 2.8625 mol

4 moles Fe(s) react with 3 moles O₂(g)

0.98 mol Fe(s) react completely with ? moles O₂(g)

= 0.735 mol O₂

So the limiting reactant is Fe

14) N₂(g) + 3 H₂(g) → 2 NH₃(g)

1 mole N₂ reacts with 3 moles H₂

so 6 moles of N₂ will react completely with 18 moles H₂

but only 10 moles of Hydrogen present so it is the limiting reactant

3 moles of H₂ gives 2 moles NH₃

10 moles of H₂ will give ? moles NH₃

= (10 * 2) / 3 = 6.67 moles NH₃

15) B₂O₃(s) + 3 C(s) + 3 Cl₂(g) → 2BCl₃(g) + 3 CO(g)

number of moles of BCl₃ produced = 700 g / 117.17 g/mol = 5.97 moles

3 moles of C produce 2 moles BCl₃

? moles of C produces 5.97 mole BCl₃

= (5.97 x 3) / 2 = 8.96 moles C

16) Fe₂O₃(s) + 3 CO(g) → 2 Fe(s) + 3CO₂(g)

1 mole of Fe₂O₃ gives 3 moles CO₂

? mole of Fe₂O₃ gives 7.4 moles CO₂

= 2.47 moles Fe₂O₃

3 moles of CO gives 3 moles of CO₂

so 7.4 moles of CO will produce the required amount of CO₂ (7.4)

b.final

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.