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3 years ago

What is the molar mass off a substance?

Chemistry

2 answers:

Anon25 [30]3 years ago

4 0

The masses of the elements added together in the formula

aalyn [17]3 years ago

3 0

It is the mass of 1 mole in that substance

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Vitamin C contains only carbon, hydrogen, and oxygen. When a 1.00 g was combusted, 1.4991 g of CO2 and 0.4092 g of H2O were obta

Alina [70]

The empirical formula for this vitamin : C₃H₄O₃

<h3>Further explanation </h3>

The empirical formula is the smallest comparison of atoms of compound =mole ratio of the components

The principle of determining empirical formula

Determine the mass ratio of the constituent elements of the compound.
Determine the mole ratio by dividing the percentage by the atomic mass

Mass of C in CO₂ :(MW C = 12 g/mol, CO₂=44 g/mol)

$\tt \dfrac{12}{44}\times 1.4991=0.409~g$

Mass of H in H₂O :(MW H = 1 g/mol, H₂O = 18 g/mol)

$\tt \dfrac{2.1}{18}\times 0.4092=0.0455~g$

Mass O = Mass sample - (mass C + mass H) :

$\tt 1-(0.409+0.0455)=0.5455~g$

mol ratio C : H : O =

$\tt \dfrac{0.409}{12}\div \dfrac{0.0455}{1}\div \dfrac{0.5455}{16}\\\\0.0341\div 0.0455\div 0.0341\rightarrow 1\div 1.33\div 1=3\div 4\div 3$

5 0

3 years ago

Is this correct? also for the mass i have to round it to the closest whole number

11Alexandr11 [23.1K]

A lithium atom has 3 protons and 3 electrons. It can lose one of its electrons, making it an ion. It now has more positive protons than electrons so it has an overall positive charge. Overall charge is +1

8 0

3 years ago

Determine the freezing point and boiling point of a solution that has 68.4 g of sucrose

Ymorist [56]

Answer:

Freezing T° of solution = - 3.72°C

Boiling T° of solution = 101.02°C

Explanation:

To solve this we apply colligative properties. Firstly, freezing point depression:

ΔT = Kf . m . i

ΔT = Freezing T° of pure solvent - Freezing T° of solution

Kf = Cryoscopic constant, for water is 1.86 °C/m

m = molality (moles of solute in 1kg of solvent)

i = Ions dissolved in solution

Our solute is sucrose, an organic compound so no ions are defined. i = 1.

Let's determine the moles: 68.4 g . 1mol/ 342g = 0.2 moles

molality = 0.2 mol / 0.1kg of water = 2 m

We replace data: ΔT = 1.86°C/m . 2m . 1

Freezing T° of solution = - 3.72°C

Now, we apply elevation of boiling point: ΔT = Kb . m . i

ΔT = Boiling T° of solution - Boiling T° of pure solvent

Kf = Ebulloscopic constant, for water is 0.512 °C/m

We replace:

Boiling T° of solution - Boiling T° of pure solvent = 0.512 °C/m . 2 . 1

Boiling T° of solution = 0.512 °C/m . 2 . 1 + 100°C → 101.02°C

6 0

3 years ago

The number of electrons in neutral atoms of the elements

Ksivusya [100]

The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.

4 0

3 years ago

A particular chemical reaction is exergonic. What can you say about the relationship between the reactants and the products in t

ozzi

Answer:

Products have a lower total Gibbs free energy in comparison with the reagents total Gibbs free energy.

Explanation:

Hello,

Exergonic chemical reactions are those that the overall Gibbs free energy is negative, it means that the products have a lower total Gibbs free energy, turning out into a spontaneous chemical reaction. Such reactions are thermodynamically possible under standard conditions and they usually release heat.

Best regards.

7 0

3 years ago