Atomic Mass Of Naoh



Atomic Mass of Sodium Atomic mass of Sodium is 22.9897 u. Since the molar mass of NaOH is 40 g/mol, we can divide the 90 g of NaOH by the molar mass (40 g/mol) to find the moles of NaOH. This the same as multiplying by the reciprocal of 40 g/mol. If the equation is arranged correctly, the mass units (g) cancel out and leave moles as the unit.

Since we kept the definition of an amu the same, but changed that of the mole, what we see is that 1 mole of carbon-12 using these units would have to weigh 24 g (the molar mass), even though its atomic mass would still be 12. Exact Mass: 39.992509 g/mol: Computed by PubChem 2.1 (PubChem release 2019.06.18) Monoisotopic Mass: 39.992509 g/mol: Computed by PubChem 2.1 (PubChem release 2019.06.18) Topological Polar Surface Area: 1 Ų: Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18) Heavy Atom Count: 2: Computed by PubChem: Formal Charge: 0: Computed. Molar Mass of NaOH; Oxidation State of NaOH. Caustic Soda Lye Soda Lye Sodium Hydrate Naoh White Caustic. Dihydrogen - H 2.

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Atomic Weight Practice Problems

We know that density = mass/volume

Therefore, mass = density * volume

Given density of 98% H2SO4 = 1.84g/mL

Therefore, 1mL of 98% H2SO4 will weigh – 1.84 * 1 = 1.84g

Hence, 100mL will weigh 1.84 * 100 = 184g

How to calculate mass of naoh

Since concentration is given as 98% by mass, 184g of the solution will contain 0.98 * 184 = 180.32g of H2SO4.

Molar mass of H2SO4 = 98.1g

Therefore, 180.32g constitutes 1.84 moles.

The reaction between NaOH and H2SO4 is as follows:

2NaOH + H2SO4 -> Na2SO4 + 2H2O

Therefore, to neutralize 1 mole of H2SO4, we need 2 moles of NaOH. So, to neutralize 1.84 moles, we need 1.84*2=3.68 moles of NaOH

Molar mass of NaOH = 40

So, 3.68 moles constitutes 147g of NaOH

We know that 1 litre of 1M NaOH contains 40g of NaOH

So, 1 litre of 0.1M NaOH contains 4g of NaOH

Therefore, to get 147g of NaOH, we need to take 147/4 = 36.76 litres of 0.1M NaOH.

Hence, 36.76 litres of 0.1M NaOH is required.

Learning Objective

  • Convert between the mass and the number of moles, and the number of atoms, in a given sample of compound

How To Calculate Mass Of Naoh

Key Points

  • The molar mass of a compound is equal to the sum of the atomic masses of its constituent atoms in g/mol.
  • Although there is no physical way of measuring the number of moles of a compound, we can relate its mass to the number of moles by using the compound’s molar mass as a direct conversion factor.
  • To convert between mass and number of moles, you can use the molar mass of the substance. Then, you can use Avogadro’s number to convert the number of moles to number of atoms.

Terms

  • moleThe amount of substance that contains as many elementary entities as there are atoms in 12 g of carbon-12.
  • dimensional analysisThe analysis of the relationships between different physical quantities by identifying their fundamental dimensions (such as length, mass, time, and electric charge) and units of measure (such as miles vs. kilometers, or pounds vs. kilograms vs. grams) and tracking these dimensions as calculations or comparisons are performed.
  • molar massThe mass of a given substance (chemical element or chemical compound) divided by its amount of substance (mol), in g/mol.

Chemists generally use the mole as the unit for the number of atoms or molecules of a material. One mole (abbreviated mol) is equal to 6.022×1023 molecular entities (Avogadro’s number), and each element has a different molar mass depending on the weight of 6.022×1023 of its atoms (1 mole). The molar mass of any element can be determined by finding the atomic mass of the element on the periodic table. For example, if the atomic mass of sulfer (S) is 32.066 amu, then its molar mass is 32.066 g/mol.

By recognizing the relationship between the molar mass (g/mol), moles (mol), and particles, scientists can use dimensional analysis convert between mass, number of moles and number of atoms very easily.

Atomic

Determining the Molar Mass of a Compound

In a compound of NaOH, the molar mass of Na alone is 23 g/mol, the molar mass of O is 16 g/mol, and H is 1 g/mol. What is the molar mass of NaOH?

[latex]Na+O+H=NaOH[/latex]

[latex]23 space text{g/mol} +16 space text{g/mol}+ 1 space text{g/mol} = 40 space text{g/mol}[/latex]

The molar mass of the compound NaOH is 40 g/mol.

Converting Mass to Number of Moles

How many moles of NaOH are present in 90 g of NaOH?

Since the molar mass of NaOH is 40 g/mol, we can divide the 90 g of NaOH by the molar mass (40 g/mol) to find the moles of NaOH. This the same as multiplying by the reciprocal of 40 g/mol.

If the equation is arranged correctly, the mass units (g) cancel out and leave moles as the unit.

[latex]90 g space text{NaOH} times frac{1 space mol}{40 g} = 2.25 space text{mol NaOH}[/latex]

There are 2.25 moles of NaOH in 90g of NaOH.

Converting Between Mass, Number of Moles, and Number of Atoms

How many moles and how many atoms are contained in 10.0 g of nickel?

According to the periodic table, the atomic mass of nickel (Ni) is 58.69 amu, which means that the molar mass of nickel is 58.69 g/mol. Therefore, we can divide 10.0 g of Ni by the molar mass of Ni to find the number of moles present.

Using dimensional analysis, it is possible to determine that:

[latex]10:g:Ni times frac{1:mol Ni}{58.69g Ni} = 0.170: mol:Ni[/latex]

To determine the number of atoms, convert the moles of Ni to atoms using Avogadro’s number:

[latex]0.170:moles:Ni times frac {6.022×10^{23} atoms Ni}{1:mol Ni} = 1.02times10^{23}:atoms:Ni[/latex]

Given a sample’s mass and number of moles in that sample, it is also possible to calculate the sample’s molecular mass by dividing the mass by the number of moles to calculate g/mol.

What is the molar mass of methane (CH4) if there are 0.623 moles in a 10.0g sample?

[latex]frac{10.0 g CH_4}{0.623 mol CH_4} = 16.05 g/mol CH_4 [/latex]

The molar mass of CH4 is 16.05 g/mol.

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Steve Lower’s Website
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http://en.wikipedia.org/wiki/Dimensional_analysis
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http://en.wikipedia.org/wiki/molar%20mass
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