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Sodium hydroxide reacts with aluminum and water to produce hydrogen gas: 2 Al(s) + 2 NaOH(aq) + 6 H2O(l) → 2 NaAl(OH)4(aq) + 3 H

lianna [129]

Answer:

The mass of hydrogen gas formed is 0.205 grams

Explanation:

Step 1: Data given

Mass of 1.83 grams of Al

Mass of NaOH = 4.30 grams

Molar mass of Al = 26.98 g/mol

Molar mass of NaOH = 40 g/mol

Step 2: The balanced equation:

2 Al(s) + 2 NaOH(aq) + 6 H2O(l) → 2 NaAl(OH)4(aq) + 3 H2(g)

Step 3: Calculate moles of Al

Moles Al = mass Al / Molar mass Al

Moles Al = 1.83 grams / 26.98 g/mol

Moles Al = 0.0678 moles

Step 4: Calculate moles of NaOH

Moles NaOH = 4.30 grams / 40 g/mol

Moles NaOH = 0.1075 moles

Step 5: Calculate limiting reactant

For 2 moles of Al, we need 2 moles of NaOH

Aluminium is the limiting reactant. It will completely be consumed ( 0.0678 moles)

NaOH is in excess. There will react 0.0678 moles

There will remain 0.1075 - 0.0678 = 0.0397 moles

Step 6: Calculate moles of hydrogen

For 2 moles of Al, we need 2 moles of NaOH, to produce 3 moles of hydrogen

For 0.0678 moles of Al, there is produced 0.0678 *3/2 = 0.1017 moles of H2

Step 7: Calculate mass of H2

Mass of H2 = Moles H2 * Molar mass of H2

Mass of H2 = 0.1017 moles * 2.02 g/mol

Mass of H2 = 0.205 grams

The mass of hydrogen gas formed is 0.205 grams

6 0

3 years ago

A 46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the

horrorfan [7]

Answer : (C) Hafnium is the most likely identity of the given substance.

Solution : Given,

Mass of given substance (m) = 46.9 g

Volume of given substance (V) = 3.5 $Cm^{3}$

First, find the Density of given substance.

Formula used :

$Density=\frac{\text{Mass of given substance}}{\text{Voume of given substance}}$

Now,put all the values in this formula, we get

$Density=\frac{46.9 g}{3.5 Cm^{3} }$ = 13.4 g/ $Cm^{3}$

So, we conclude that the density of given substance (13.4 g/ $Cm^{3}$ ) is approximately equal to the density of Mercury and Hafnium (13.53 and 13.31 g/ $Cm^{3}$ respectively).

According to the question the substance is solid at room temperature but Mercury is liquid at room temperature. So, Mercury is not identical to the given substance.

Another element i.e, Hafnium is the element whose density is approximately equal to the given substance and also solid at room temperature. And we know that the melting point of solid is high.

So, Hafnium is the most likely element which is the identity of the given substance.

3 0

3 years ago

Read 2 more answers

The acidity of normal rain water is due to ______. a) SO2 b) CO2 c) NO2 d) NO

Viktor [21]

The correct answer choice is CO₂ (B)

Rainwater naturally contains acids derived from carbon dioxide in the air and reacts with water vapor to form weak acids

H₂O + CO₂ ---> H₂CO₃

<h3>Further Explanation</h3>

Rainwater can cause damage to buildings, animals or plants due to acid rain

Acid rain occurs because other gases in the air mix with toxic gases to form acids

Rainwater naturally contains acids derived from carbon dioxide in the air and reacts with water vapor to form weak acids

H₂O + CO₂ ---> H₂CO₃

However, due to exhaust gases from industry, motor vehicles, or power plants that use fossil fuels containing sulfur to produce sulfur dioxide gas which will produce sulfuric acid

Sulfur combustion from fossil fuels

S + O₂ ----> SO₂

SO₂ produced from this exhaust gas reacts with O₂ oxygen which oxidizes SO₂ to SO₃

SO₂ + O₂ ----> SO₃

SO3 formed reacts with water vapor in the air to produce sulfuric acid as acid rain

SO₃ + H₂O ---> H₂SO₄

To reduce the pollution from this fossil fuel, various studies are now carried out as substitute energy that is more environmentally friendly such as solar energy and so on

<h3>Learn more </h3>

Acid rain is a secondary pollutant

brainly.com/question/1324440

The impact of from acid rain

brainly.com/question/8208861

Air pollution

brainly.com/question/1232950

Keywords: acid rain, air pollution, SO₃, H₂SO₄, fossil fuel

6 0

4 years ago

Read 2 more answers

Solid magnesium has mass of 1300g and a volume of 743cm . what's the density of magnesium?

Lilit [14]

D = m / V

d = 1300 g / 743 cm³

d = 1.749 g/cm³

3 0

3 years ago

Solid a is a very hard electrical insulator in solid as well as in molten state and melts at extremely high temperature. What ty

devlian [24]

This is covalent network type of solid.

For example, silicon dioxide (SiO₂) is covalent network solid with covalent bonding.

Covalent network solid is a chemical compound (or element) in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material.

Silicon(IV) oxide has continuous three-dimensional network of SiO₂ units and diamond has sp3 hybridization.

This solids do not have free electrons so they are good insulators.

They have strong covalent bonds, so they melt at extremely high temperature.

Other examples are quartz, diamond, and silicon carbide.

More about network solid: brainly.com/question/15548648

#SPJ4

5 0

2 years ago