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3 years ago

Calculate the number of moles in a 2.98 g sample of aluminum.

1 answer:

3 0

Molar mass <span>Aluminium ( Al) = 26.98 g/mol

1 mole ------------ 26.98 g
? mole ----------- 2.98 g

moles Al = 2.98 x 1 / 26.98

moles Al = 2.98 / 26.98

= 0.110 moles

hope this helps!

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A sample of water at 100°C is converted to steam after absorbing 820 kJ of heat. How grams of H2O are contained in the sample? A

Varvara68 [4.7K]

Since water is already at 100<span>°C all the energy is used to evaporate it.
Now we can calculate how many </span>mols of water are evaporated with 820kJ.
$N= \frac{820}{41} =20 mol$
We calculated that we got 20 mols of water evaporated. Now, all we have to do is find how many grams is a mol of water. Molar mass of water is <span>20.16 g/mol.
</span>The final answer is:
$m=20*20.16=403.2g$

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3 years ago

Given that you have 14.5 moles of n2, how many moles of h2 are theoretically needed to produce 30.0 moles of nh3 according to re

erastovalidia [21]

45 moles of H₂ are theoretically needed to produce 30.0 moles of NH₃

<h3>Further explanation</h3>

Stoichiometry in Chemistry learn about chemicals mainly emphasizes quantitative, such as the calculation of volume, mass, number, which is related to numbers, molecules, elements, etc.

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

In the reaction there are also manifestations of reagent substances namely gas (g), liquid (liquid / l), solid (solid / s) and solution (aqueous / aq).

The concentration of a substance can be expressed in several quantities such as moles, percent (%) weight/volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.

Mole

The mole itself is the number of particles contained in a substance amounting to 6.02.10²³

Mole can also be sought if the amount of substance mass and its molar mass is known

$\large{\boxed{\boxed{\bold{mol=\frac{mass}{molar\:mass}}}}$

Reaction that happens :

N₂ +3H₂ ⇒ 2NH₃

mole N₂ : H₂ : NH₃ = 1 : 3 : 2

To produce 30.0 moles of NH₃,

H₂ needed :

$mole~H_2~=~\frac{3}{2}\times~30~mole$

mole H₂ = 45 mole

N₂ needed :

$mole~N_2~=~\frac{1}{2}~\times~30$

mole N₂ = 15 mole

So the minimum N₂ needed is: 15 mole

14.5 moles of N₂ can only produce NH₃ :

$mole~NH_3~=~\frac{2}{1}~\times~14.5$

mole NH₃ = 29 mole

<h3>Learn more </h3>

The mass of one mole of raindrops

brainly.com/question/5233234

moles of NaOH

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moles of water you can produce

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Keywords: mole, NH₃, N₂, H₂

7 0

3 years ago

Read 2 more answers

How many Grams of NO is produced if 12g of O2 is combined with excess ammonia?

stich3 [128]

Answer:

Explanation:

moles O2 = mass / Mr = 12 / 2(16.0) = 0.375

ratio O2 : NO = 5:4

moles NO produced = 0.375 * 4/5 = 0.3

mass NO = Mr * mol = (14.0+16.0) * 0.3 = 9g

5 0

3 years ago

How much time would it take for 336 mg of copper to be plated at a current of 5.6 A ? Express your answer using two significant

schepotkina [342]

Answer:

1.8 × 10² s

Explanation:

Let's consider the reduction that occurs upon the electroplating of copper.

Cu²⁺(aq) + 2 e⁻ ⇒ Cu(s)

We will establish the following relationships:

1 g = 1,000 mg
The molar mass of Cu is 63.55 g/mol
When 1 mole of Cu is deposited, 2 moles of electrons circulate.
The charge of 1 mole of electrons is 96,486 C (Faraday's constant).
1 A = 1 C/s

The time that it would take for 336 mg of copper to be plated at a current of 5.6 A is:

$336mgCu \times \frac{1gCu}{1,000mgCu} \times \frac{1molCu}{63.55gCu} \times \frac{2mole^{-} }{1molCu} \times \frac{94,486C}{1mole^{-}} \times \frac{1s}{5.6C} = 1.8 \times 10^{2} s$

3 0

3 years ago

Consider the reaction. mc014-1.jpg How many grams of methane should be burned in an excess of oxygen at STP to obtain 5.6 L of c

garri49 [273]

The reaction for the combustion of methane can be expressed as follows.
CH4 + 2O2 --> CO2 + 2H2O
We solve first for the amount of carbon dioxide in moles by dividing the given volume by 22.4L which is the volume of 1 mole of gas at STP.
moles of CO2 = (5.6 L) / (22.4 L/1 mole)
moles of CO2 = 0.25 moles
Then, we can see that every mole of carbon dioxide will need 1 mole of methane
moles methane = (0.25 moles CO2) x (1 moles O2/1 mole CO2)
= 0.25 moles CH4
Then, multiply this by the molar mass of methane which is 16 g/mole. Thus, the answer is 4 grams methane.

5 0

3 years ago

Read 2 more answers