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4 years ago

HELP ASAP

Chemistry

1 answer:

lora16 [44]4 years ago

5 0

Answer:

the correct answer is D

Explanation:

The density of gold is 19.4g/cm

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Cryolite, Na3AlF6(s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. Balance the equation f

Korvikt [17]

Answer:

$55.2kgNa_{3}AlF_{6}$

Explanation:

1. First balance the equation for the synthesis of cryolite:

$Al_{2}O_{3}_{(s)}+6NaOH_{(l)}+12HF_{(g)}=2Na_{3}AlF_{6}+9H_{2}O_{(g)}$

2. Find the limiting reagent between the $Al_{2}O_{3},NaOH$ and $HF$

- First calculate the number of moles of each compound using its molar mass and the mass that reacted completely:

$13.4kgAl_{2}O_{3}*\frac{1molAl_{2}O_{3}}{101.96gAl_{2}O_{3}}*\frac{1000g}{1kg}=131molesAl_{2}O_{3}$

$55.4kgNaOH*\frac{1molNaOH}{40kgNaOH}*\frac{1000g}{1kg}=1385molesNaOH$ $55.4kgHF*\frac{1molHF}{20kgHF}*\frac{1000g}{1kg}=2770molesHF$

- Divide the number of moles obtained between the stoichiometric coefficient of each compound in the chemical reaction:

$Al_{2}O_{3}:\frac{131}{1}=131$

$NaOH:\frac{1385}{6}=231$

$HF:\frac{2770}{12}=231$

The $Al_{2}O_{3}$ is the limiting reagent because it has the smallest number.

3. Find the mass of cryolite produced:

$13.4kgAl_{2}O_{3}*\frac{1molAl_{2}O_{3}}{0.10196kgAl_{2}O_{3}}*\frac{2molesNa_{3}AlF_{6}}{1molAl_{2}O_{3}}*\frac{0.20994kgNa_{3}AlF_{6}}{1molNa_{3}AlF_{6}}=55.2kgNa_{3}AlF_{6}$

3 0

4 years ago

Calcium hydride reacts with water to form calcium hydroxide (aqueous) and hydrogen gas. Write a balanced chemical equation for t

DanielleElmas [232]

Answer:

$CaH_2(s) +2H_2O(l) \rightarrow Ca(OH)_2 (aq) + 2H_2 (g)$

Explanation:

$CaH_2(s) +H_2O(l) \rightarrow Ca(OH)_2 (aq) + H_2 (g)$

In this reaction, calcium is balanced in either side. No. of atoms of 'H' and 'O' are not balanced. To balance O atoms, multiply $H_2O$ by 2. Now the reaction becomes:

$CaH_2(s) +2H_2O(l) \rightarrow Ca(OH)_2 (aq) + H_2 (g)$

Now, to balance H atoms, multiply H2 by 2.

$CaH_2(s) +2H_2O(l) \rightarrow Ca(OH)_2 (aq) + 2H_2 (g)$

Now, each element is balanced.

8 0

3 years ago

Help a #QUEEN out PLSSSS!!!

spayn [35]

Co2 and Fe are the products the other two are reactants.

5 0

3 years ago

John dalton was the first person recorded as thinking that matter was ultimately composed of atoms. true or false

Alona [7]

The statement is false. It was Democritus, a Greek philosopher, who first theorized that matter was ultimately composed of atoms. His ideas were not widely accepted in his time (460-370 B.C), but during the 19th century, John Dalton proposed this theory and gained broad acceptance.

3 0

3 years ago

Read 2 more answers

Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation isC7H6

prisoha [69]

Answer:

For a: The mass of acetic anhydride needed is 73.91 grams.

For b: The theoretical yield of aspirin is 130.43 grams.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)