12. How many moles of atoms are present in 154 g of Na2O?
A) 2.48 mol
B) 7.45 mol
C) 51.3 mol
D) 0.827 mol

Answers

Answer 1

Answer:

[tex]\boxed {\boxed {\sf A. \ 2.48 \ mol \ Na_2O}}[/tex]

Explanation:

We are asked to convert an amount in grams to moles. To do this, we use the molar mass. This is the number of grams in one mole of a substance. It is the same value numerically as the atomic mass on the Periodic Table, however the units are grams per mole, not atomic mass units.

Look up the molar masses for the individual elements.

Sodium (Na): 22.9897693 g/mol Oxygen (O): 15.999 g/mol

Look back at the formula: Na₂O. Notice there is a subscript of 2 after sodium. This means there are 2 atoms of sodium in every molecule, so we have to multiply sodium's molar mass by 2 before adding oxygen's.

Na₂O: 2(22.9897693 g/mol)+ 15.999 g/mol = 61.9785386 g/mol

Set up a ratio using the molar mass.

[tex]\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}[/tex]

Multiply by the given number of grams.

[tex]154 \ g \ Na_2O*\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}[/tex]

Flip the ratio so the grams of sodium oxide can cancel each other out.

[tex]154 \ g \ Na_2O*\frac {1 \ mol \ Na_2O}{61.9785386 \ g \ Na_2O}[/tex]

[tex]154 *\frac {1 \ mol \ Na_2O}{61.9785386 }[/tex]

[tex]\frac {154}{61.9785386 } \ mol \ Na_2O[/tex]

[tex]2.48473106141 \ mol \ Na_2O[/tex]

The original measurement of grams given has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.

2.48473106141

The 4 in the thousandth place tells us to leave the 8.

[tex]2.48 \ mol \ Na_2O[/tex]

There are 2.48 moles of sodium oxide in 154 grams, so choice A is correct.


Related Questions

Match each definition to the appropriate term.
Sum of the internal energy plus the product of the pressure and volume for a reaction
The extent of randomness in a system
The condition that a reaction takes place without outside help
Difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature
Solution in which no more solute can be dissolved in the solvent

Answers

Answer:

Enthalpy, Entropy, Spontaneity, Gibbs free energy, saturated solution

Explanation:

Enthalpy is defined as the heat released or the heat absorbed during the process at a constant pressure which is equal to the Enthalpy shift. Enthalpy is also called as heat content and it is the sum total of internal energy and the product of the volume and pressure of a system.

Entropy is defined as the measure of randomness of a system or the disorder of the system.

Spontaneity is defined as the condition of being spontaneous. It is the condition where a reaction takes place without any help from outside.

Gibbs free energy is defined as the energy that is used to quantify the maximum work done in a thermodynamic system at constant temperature and pressure. It is the also known as the Gibbs energy or function.

Saturated solution is defined as the solution where the maximum amount of the dissolved solute is present in the solvent. In case of a saturated solution, the extra solute does not dissolve. In order words, it is a solution where no more solute can dissolved in solvent.

The sum of the internal energy plus the product of the pressure and volume for a reaction represents Enthalpy , Entropy is the extent of randomness in a system, Spontaneity is that condition that a reaction takes place without outside help, Gibb's free energy is the difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature and Saturated solution in which no more solute can be dissolved in the solvent.

Which properties will define chemical reaction?

Thermodynamically chemical reactions will be define by considering the properties like entropy, enthalpy, free energy, internal energy, temperature and many more.

Enthalpy of the reaction tells about the total amount of heat released or absorbed during a chemical reaction, and it is calculated as sum of the internal energy plus the product of the pressure and volume for a reaction.Entropy of any reaction tells about the randomness and uncertainty present within the molecule or atoms.Spontaneity of any chemical reaction tells about the ease of completion of that reaction. Gibb's free energy is the total energy involved in that reaction and represented as difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature.Saturated solutions are those solutions in which all solute get completely dissolved, no solute will remain undissolved.

Hence correct answers are Enthalpy , Entropy ,Spontaneity, Gibb's free energy and Saturated solutions.

To know more about saturated solutions, visit the below link:
https://brainly.com/question/4529762

Why are diamonds unevenly distributed on Earth?

Soil forms only in places where rock particles are deposited.
Soil forms only in places where larger rocks are broken into smaller rocks.
Soil forms only within the Earth under heavy pressure.
Soil forms in the air and is then deposited mainly in places that get a lot of rain.

Answers

Answer:

Why aren't diamonds found evenly distributed on Earth? Diamonds are only formed under specific conditions that involve geological processes, such as volcanic activities and plate movements. Since these conditions and processes only take place in certain areas, you can only find diamonds in these special places.

Explanation:

What is the vapor pressure of an aqueous solution that has a solute mole fraction of 0.1000? The vapor pressure of water is 25.756 mmHg at 25 °C.​

Answers

Answer:

χsolvent = 1.0000 - 0.1000 = 0.9000

Use Raoult's Law:

Psolution = (χsolvent) (P°solvent)

x = (0.900) (25.756)

x = 23.18 mmHg (to four sig figs)

The vapor pressure of an aqueous solution is  x = 23.18 mmHg (to four sig figs)

χsolvent = 1.0000 - 0.1000 = 0.9000

Use Raoult's Law:

P solution = (χsolvent) (P°solvent)

x = (0.900) (25.756)

x = 23.18 mmHg (to four sig figs)

What is an aqueous solution?

An aqueous answer is one in which the solvent is liquid water. that is, solute (dissolved) ions and molecules are surrounded by water molecules and integrated into the network of bonds within the water. The dissolved species then spread in the course of the water.

A solution wherein water is the solvent is called an aqueous solution. although water is an exceptional solvent, now not the whole thing dissolves comfortably in the water.

Aqueous' in a chemical equation suggests that the cloth dispersed in water (an answer in water). As an example, when we pour sodium hydroxide answer into dilute hydrochloric acid, we get an aqueous solution of sodium chloride. The liquid is used to signify the formation of liquid materials in response.

Learn more about the aqueous solution here: https://brainly.com/question/19587902

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