All categories

3 years ago

An atom has 4 protons 4 neutrons, and 4 electrons. This atom has a mass number of

Chemistry

2 answers:

Art [367]3 years ago

6 0

Answer:

Explanation:

Hope it helps you

kipiarov [429]3 years ago

5 0

Its nucleus also contains two neutrons. Since 2 + 2 = 4, we know that the mass number of the helium atom is 4. Finally, the helium atom also contains two electrons since the number of electrons must equal the number of protons.

You might be interested in

CH3CH2OH + 302 → 2002 + 3H20

Softa [21]

Answer:

Oxygen gas

Explanation:

Given expression:

CH₃CH₂OH + 3O₂ → 2CO₂ + 3H₂O

Number of moles of oxygen gas = 1 mole

Number of moles of ethanol = 1 mole

Unknown:

The limiting reactant = ?

Solution:

The limiting reactant is the reactant in short supply in a chemical reaction. To find this specie, we always us the number of moles.

From the equation of the reaction:

1 mole of ethanol would require 3 moles of oxygen gas

But we have been given just 1 mole of oxygen gas instead of 3moles.

Therefore, oxygen gas is the limiting reactant.

3 0

3 years ago

A compound has a percent composition of 54.5% carbon, 9.3% hydrogen and 36.2 % oxygen.If its molar mass is 88 g/mol, what is its

drek231 [11]

Answer:

C₄H₈O₂.

Explanation:

Firstly, we can calculate the no. of moles (n) of each component using the relation:

n = mass/atomic mass,

mol C = mass/(atomic mass) = (54.5 g)/(12.0 g/mol) = 4.54 mol.

mol H = mass/(atomic mass) = (9.3 g)/(1.0 g/mol) = 9.3 mol.

mol O = mass/(atomic mass) = (36.2 g)/(16.0 g/mol) = 2.26 mol.

To get the empirical formula, we divide by the lowest no. of moles (2.26 mol) of O:

∴ C: H: O = (4.54 mol/2.26 mol) : (9.3 mol/2.26 mol) : (2.26 mol/2.26 mol) = 2: 4: 1.

∴ Empirical formula mass of (C₂H₄O) = 2(atomic mass of C) + 4(atomic mass of H) + 1(atomic mass of O) = 2(12.0 g/mol) + 4(1.0 g/mol) + (16.0 g/mol) = 44.0 g/mol.

∴ Number of times empirical mass goes into molecular mass = (88.0 g/mol)/(44.0 g/mol) = 2.0 times.

∴ The molecular formula is, 2(C₂H₄O), that is; (C₄H₈O₂)

4 0

3 years ago

A three-step process for producing molten iron metal from Fe2O3 is: 3Fe2O3 + CO → 2Fe3O4 + CO2 Fe3O4 + CO → 3FeO + CO2 FeO + CO

miskamm [114]

Answer:

There is 100.4652 kg of iron produced from 390 kg of Fe2O3

Explanation:

Step 1: Given data

3Fe2O3 + CO → 2Fe3O4 + CO2

Fe3O4 + CO → 3FeO + CO2

FeO + CO → Fe + CO2

Mass of Fe2O3 = 390 kg = 390000 grams

Molar mass of Fe2O3 = 159.69 g/moles

Step 2: Calculate moles of Fe2O3

Moles of Fe2O3 = mass of Fe2O3 / Molar mass of Fe2O3

Moles of Fe2O3 = 390000 grams / 159.69 g/moles = 2442.2 moles

Step 3: Calculate expected moles of Fe3O4

In the first equation, for 3 moles of Fe2O3 consumed ,we get 2 moles of Fe3O4. The mole ratio is 3:2

This means if we consume 2442.2 moles of Fe2O3, there will be produced 2/3 * 2442.2 = 1628.2 moles of Fe3O4

Since the yield for the step is only 84.6 %

This will be 0.846 * 1628.2 = 1377.4 moles of Fe3O4

Step 4: Calculate expected moles of FeO

In the second equation, for 1 mole of Fe3O4 consumed, there is produced 3 moles of FeO

This means for 1377.4 moles of Fe3O4 consumed, there is 3*1377.4 = 4132.2 moles of FeO produced

Since the yield for the step is only 50.8%

This will be 0.508 * 4132.2 = 2099.2 moles of FeO

Step 5: Calculate expected moles of Fe

In the third equation, for 1 mole of FeO consumed, there is produced 1 mole of Fe.

This means for 2099.2 moles of FeO consumed, there is also 2099.2 moles of Fe produced

Since the yield is only 85.7%

This will be 0.857 * 2099.2 = 1799 moles of Fe

Step 6: Calculate mass of Fe

Mass of Fe = moles of Fe * Molar mass of Fe

Mass of Fe = 1799 moles of Fe * 55.845 g/moles = 100465.2 grams = 100.4652 kg of Fe

There is 100.4652 kg of iron produced from 390 kg of Fe2O3

6 0

4 years ago

Why dose heating increase the speed at which a solution dissolved in water

emmainna [20.7K]

Answer:

The added energy in the hot water causes water molecules to move faster and sucrose molecules to vibrate faster.

Explanation:

This added movement tends to make the bonds between sucrose molecules easier to overcome.

Hope it helps :-)

4 0

3 years ago

At room temperature, the surface tension of water is 72.0 mJ·m–2. What is the energy required to change a spherical drop of wate

Keith_Richards [23]

It is given that the surface area of sphere is 4 π r² and its volume is (4/3 π r³)
With a diameter of 1.2 mm you have a radius of 0.6 mm so the surface area about 4.5 mm² and the volume is about 0.9 mm³
The total surface energy of the original droplet is (4.5 x 10⁻⁶ m x 72) = 3.24 x 10⁻⁴mJ
The five smaller droplets need to have the same volume as the original so:
5 V = 0.9 mm³ so the volume of smaller sphere will equal 0.18 mm³
Since this smaller volume still have volume (4/3 π r³) so r = 0.35 mm
Each of the smaller droplets has a surface are = 1.54 mm²
The surface energy of the 5 smaller droplet is then (5 x 1.54 x 10⁻⁶ m x 72) = 5.54 x 10⁻⁴ mJ
From this radius the surface energy of all smaller droplets is 5.54 x 10⁻⁴ and the difference in energy is (5.54 x 10⁻⁴) - (3.24 x 10⁻⁴) = 2.3 x 10⁻⁴ mJ
Therefore we need about 2.3 x 10⁻⁴ mJ of energy to change a spherical droplet of water of diameter 1.2 mm into 5 identical smaller droplets

5 0

3 years ago