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3 years ago

Please help, it's a task in science and I'm really bad at this subject.

Chemistry

1 answer:

Nastasia [14]3 years ago

6 0

Answer:

1. solid

2. liquid

3. plasma

4. gas

Those are the four parts of matter.

Explanation:

I hope this helps.

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How many grams of Fe3O4 are required to react completely with 300 grams of H2?

vekshin1

Answer:

2023.04 g

Explanation:

Magnetite reacts with hydrogen to produce Iron metal and steam. Steam instead of water is produced as the reaction occurs at temperatures above the boiling point of water.

Fe₃O₄ + 4 H₂ → 3 Fe +4 H₂O

From the equation, 1 mole of Fe₃O₄ reacts with 4 moles of H₂.

69.76 grams of H₂ has the following number of moles.

Number of moles= mass/RAM

=69.76/2

=34.88 moles.

The reaction ratio of Fe₃O₄ to H₂ is 1:4

Thus number of moles of magnetite= (1×34.88)/4

=8.72 moles.

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3 years ago

When copper metal is added to nitric acid, the following reaction takes place

zlopas [31]

Answer:

The volume of NO₂ gas collected over water at 25.0 °C is 1.68 Liters.

Explanation:

$Cu (s) + 4 HNO_3 (aq) \rightarrow Cu(NO_3)_2 (aq) + 2 H_2O (l) + 2 NO_2 (g)$

Moles of copper = $\frac{2.01 g}{63.55 g/mol}=0.03163 mol$

According to reaction, 1 mol of copper gives 2 moles of nitrogen dioxide gas.

Then 0.03613 moles of copper will give:

$\frac{2}{1}\times 0.03163 mol=0.06326 mol$ of nitrogen dioxide gas

Moles of nitrogen dioxide gas = n = 0.06326 mol

Pressure of the gas = P

P = Total pressure - vapor pressure of water

P = 726 mmHg - 23.8 mmHg = 702.2 mmHg

P = 0.924 atm (1 atm = 760 mmHg)

Temperature of the gas = T = 25.0°C =298.15 K

Volume of the gas = V

$PV=nRT$

$V=\frac{0.06326 mol\times 0.0821 atm L/mol K\times 298.15 K}{0.924 atm}$

V = 1.68 L

The volume of NO₂ gas collected over water at 25.0 °C is 1.68 Liters.

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3 years ago

A cast fossil is formed when

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The answer is D)
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3 years ago