Chemistry, 25.11.2019 21:31 melissarodrigue7

Question 1(multiple choice worth 4 points)
(05.04 mc)

what mass of co is needed to react completely with 55.0 g of fe2o3 in the reaction: fe2o3(s) + co(g) → fe(s) + co2(g)?

4.82 g co
9.64 g co
14.5 g co
28.9 g co
question 2(multiple choice worth 4 points)
(05.04 lc)

which of the following is a valid mole ratio from the balanced equation 2c3h6 + 9o2 → 6co2 + 6h2o?

one mole of c three h six over two moles of c o two
six moles of h two o over nine moles of o two
two moles of c three h six over six moles of o two
three moles of h two o over 2 moles of c o two
question 3(multiple choice worth 4 points)
(05.04 mc)

read the following chemical equation.

fe + o2 → fe2o3

which of the following fractions can be used for the mole ratio to determine the mass of fe from a known mass of fe2o3?

four over two
three over two
two over three
two over four
question 4(multiple choice worth 4 points)
(05.04 mc)

in an experiment, zinc chlorate decomposed according to the following chemical equation.

zn(clo3)2 → zncl2 + o2

(molar mass of zn(clo3)2 = 232.29 g/mol; zncl2 = 136.286 g/mol; o2 = 31.998 g/mol)

if the mass of zinc chlorate was 150 grams, which of the following calculations can be used to determine the mass of oxygen gas formed?

(150 × 1 × 232.29) ÷ (31.998 × 3) grams
(150 × 3 × 232.29) ÷ (31.998 × 1) grams
(150 × 1 × 31.998) ÷ (232.29 × 3) grams
(150 × 3 × 31.998) ÷ (232.29 × 1) grams
question 5(multiple choice worth 4 points)
(05.04 lc)

how many moles of sodium cyanide (nacn) would be needed to produce 4.2 moles of sodium sulfate (na2so4)?

h2so4 + 2nacn → 2hcn + na2so4

2.1 mol nacn
4.2 mol nacn
8.4 mol nacn
12.0 mol nacn

Answers: 1

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Answers

Answer from: guko

Answer

Answer 1 : 28.9 g of CO is needed.

Answer 2 : Six moles of $H_{2}O$ over Nine moles of $O_{2}$

Answer 3 : Four over two fraction can be used for the mole ratio to determine the mass of Fe from a known mass of $Fe_{2}O_{3}$ .

Answer 4 : Mass of $O_{2}$ = (150 × 3 × 31.998) ÷ (232.29 × 1) grams

Answer 5 : 8.4 moles of sodium cyanide (NaCN) would be needed.

Solution

Solution 1 : Given,

Given mass of $Fe_{2}O_{3}$ = 55 g

Molar mass of $Fe_{2}O_{3}$ = 159.69 g/mole

Molar mass of CO = 28.01 g/mole

Moles of $Fe_{2}O_{3}$ = $\frac{\text{ Given mass of } Fe_{2}O_{3}}{\text{ Molar mass of } Fe_{2}O_{3}}$ = $\frac{55 g}{159.69 g/mole}$ = 0.344 moles

Balanced chemical reaction is,

$Fe_{2}O_{3}(s)+3CO(g)\rightarrow 2Fe(s)+3CO_{2}(g)$

From the given reaction, we conclude that

1 mole of $Fe_{2}O_{3}$ gives → 3 moles of CO

0.344 moles of $Fe_{2}O_{3}$ gives → 3 × 0.344 moles of CO

= 1.032 moles

Mass of CO = Number of moles of CO × Molar mass of CO

= 1.032 × 28.01

= 28.90 g

Solution 2 : The balanced chemical reaction is,

$2C_{3}H_{6}+9O_{2}\rightarrow 6CO_{2}+6H_{2}O$

From the given reaction, we conclude that the Six moles of $H_{2}O$ over Nine moles of $O_{2}$ is the correct option.

Solution 3 : The balanced chemical reaction is,

$4Fe+3O_{2}\rightarrow 2Fe_{2}O_{3}$

From the given balanced reaction, we conclude that Four over two fraction can be used for the mole ratio to determine the mass of Fe from a known mass of $Fe_{2}O_{3}$ .

Solution 4 : Given,

Given mass of $Zn(ClO_{3})_{2}$ = 150 g

Molar mass of $Zn(ClO_{3})_{2}$ = 232.29 g/mole

Molar mass of $O_{2}$ = 31.998 g/mole

Moles of $Zn(ClO_{3})_{2}$ = $\frac{\text{ Given mass of }Zn(ClO_{3})_{2} }{\text{ Molar mass of } Zn(ClO_{3})_{2}}$ = $(\frac{150\times 1}{232.29})moles$

The balanced chemical equation is,

$Zn(ClO_{3})_{2}}\rightarrow ZnCl_{2}+3O_{2}$

From the given balanced equation, we conclude that

1 mole of $Zn(ClO_{3})_{2}$ gives → 3 moles of $O_{2}$

$(\frac{150\times 1}{232.29})moles$ of $Zn(ClO_{3})_{2}$ gives → $[(\frac{150\times 1}{232.29})\times 3] moles$ of $O_{2}$

Mass of $O_{2}$ = Number of moles of $O_{2}$ × Molar mass of $O_{2}$ = $[(\frac{150\times 1}{232.29})\times 3] \times 31.998 grams$

Therefore, the mass of $O_{2}$ = (150 × 3 × 31.998) ÷ (232.29 × 1) grams

Solution 5 : Given,

Number of moles of $Na_{2}SO_{4}$ = 4.2 moles

Balanced chemical equation is,

$H_{2}SO_{4}+2NaCN\rightarrow 2HCN+Na_{2}SO_{4}$

From the given chemical reaction, we conclude that

1 mole of $Na_{2}SO_{4}$ obtained from 2 moles of NaCN

4.2 moles of $Na_{2}SO_{4}$ obtained → 2 × 4.2 moles of NaCN

Therefore,

The moles of NaCN needed = 2 × 4.2 = 8.4 moles

Answer from: khenalilovespandas

The number of moles is obtained by dividing the mass by the molar mass.

1) The reaction equation is;

Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g)

Number of moles of Fe2O3 reacted = 55.0 g/160 g/mol =0.34

From the balanced reaction equation;

1 moles of Fe2O3 reacts with 3 moles of CO

0.34 moles of Fe2O3 reacts with 0.34 moles × 3 moles/1 moles

= 1.02 moles of CO

Mass of CO = 1.02 moles × 28 g/mol = 28.9 g CO

2) Looking at the balanced chemical reaction equation as shown in the question, the valid mole ratio is six moles of H two O over nine moles of O two.

3) The balanced reaction equation is; 4 Fe +3 O2 → 2Fe2O3. From this we can see that the mole ratio to determine the mass of Fe from a known mass of Fe2O3 is four over two.

4) Given that the balanced reaction equation is; Zn(ClO3)2 = ZnCl2 + 3 O2

The equation that could be used to calculate the mass of oxygen formed is;

(150 × 3 × 31.998) ÷ (232.29 × 1) grams

5) The balanced reaction equation is; H2SO4 + 2NaCN = 2HCN + Na2SO4

From the reaction equation;

2 moles of NaCN yields 1 mole of Na2SO4

4.2 moles of NaCN yields 4.2 moles × 1 mole /2 moles

= 2.1 mol NaCN

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Adozen is 12, and your needing to calculate the weight of one medium egg, so i would do 21/12=1.75 per egg, and check your answer by doing 1.75 * 12= 21 : ) : ): ): ): ) i hoped i

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Since there is the same amount of agn03 in both silver chloride and silver nitrate they produce the same amount of moles. therefore silver chloride produces the same amount of silver nitrate, so your answer is 15.0 moles of silver nitrate. i hope this !

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Question 1(multiple choice worth 4 points)
(05.04 mc)

what mass of co is needed t...

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