Molecular Mass

Molecular mass measures the mass of a molecule. It is measured by adding together the atomic masses of atoms the molecule is made of.

1,424 Questions
Chemistry
Molecular Mass

How many moles of KCl would be dissolved in 4 liters of water to make 2 Molar solution?

8 moles of KCl are needed.

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Chemistry
Atoms and Atomic Structure
Molecular Mass

How many moles of gold Au are in 3.60X10-5 of gold?

I

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Chemistry
Atoms and Atomic Structure
Molecular Mass

According to the ideal gas law what happens to the volume of a gas when the number of moles doubles?

The volumes doubles

456
Molecular Mass

What is the molecular mass of nitric acid?

63.08 g/mol I got that by adding the molar mass of one atom of hydrogen, 1.01 g/mol, one atom of nitrogen, 14.07 g/mol, and 3 atoms of oxygen, 16 g/mol each.

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Chemistry
Molecular Mass

What concentration unit is measured in moles of a solute per kilogram of solvent?

Mol is a cocentration unit !

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Chemistry
Atoms and Atomic Structure
Molecular Mass

How many moles in 300g of sulfur?

300 g sulfur is equivalent to 9,357 moles.

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Chemistry
Atoms and Atomic Structure
Molecular Mass

What is the mass of 4.00 moles of iron?

The mass of 4,00 moles of iron is 223,38 g.

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Chemistry
Atoms and Atomic Structure
Molecular Mass

What is the number of moles in 510 g of Al2S3?

510 g Al2S3 is equal to 3,396 moles.

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Molecular Mass

What is the molecular mass of C2H5OH?

A molecule of ethanol has 2 carbon atoms, 6 hydrogen atoms and 1 oxygen atom. Their atomic masses are 12, 1 and 16 in order. By adding of the masses, the molecular mass of ethanol is 12x2+1x6+16=46u.

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Chemistry
Atoms and Atomic Structure
Molecular Mass

How many moles of Fe are present in 30 grams in rust?

In the most common form of rust, Fe2O3, you would have 30 g x 1mol/160 g = 0.1875 moles
0.1875 moles Fe2O3 x 2 moles Fe/mole Fe2O3 = 0.375 moles of Fe.

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Temperature
Molecular Mass

What is the mass at 20 degrees Celsius of five liters of air?

8

789
Chemistry
Atoms and Atomic Structure
Molecular Mass

If 3 moles of a compound use 24 J of energy in a reaction what is the H reaction in J mol?

If 3 moles of a compound use 24 J of energy in a reaction, the H reaction is 8 J/mol.

456
Molecular Mass

Explain briefly why esters are less soluble in water than carboxylic acids of comparable molecular mass?

Esters are less polar than carboxylic acids, and water is a very polar solvent (like dissolves like).  Furthermore, acids can ionize and form hydrogen bonds in water, etc.

345
Chemistry
Temperature
Molecular Mass

Isobutyl alcohol has a boiling point of 108 C How would you modify the procedure used in this experiment to determine its molar mass?

The boiling point of water is only 100 C, so water can not be used to heat the flask containing Isobutyl. Heat the flask containing the Isobutyl directly or heat it in a substance that has a boiling point above 108 C

345
Chemistry
Atoms and Atomic Structure
Molecular Mass

What concentration unit is measured in moles of solute per kilogram of solvent?

The unit is mol/kg; molality is not a unit, it is a measure of concentration.

111213
Chemistry
Atoms and Atomic Structure
Molecular Mass

How many grams of carbon dioxide are present in a sample containing 80.0 moles of CO2?

80,0 moles of CO2is equal to 3 520,8 g.

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Physics
Molecular Mass

How does the mass of an object affect the force needed to move it?

Acceleration = Force/mass.

678
Chemistry
Atoms and Atomic Structure
Molecular Mass

What is the pressure of 4 moles of helium in a 50 L tank of 308 K?

The pressure is 2,02 atmospheres.

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Chemistry
Atoms and Atomic Structure
Molecular Mass

How many number of moles of glucose are present in 540 grams of glucose?

The number of moles is 2,997.

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Molecular Mass

Why do you use the term formula mass instead of molecular mass for ionic compound?

Because an ion is not a molecule.

91011
Molecular Mass

Why does ethanol have higher boiling point than butane although the latter has higher relative molecular mass?

Ethanol has a higher boiling point because of chemical bonding. Ethanol is an alcohol. Specifically hydrogen bonding. Ethanol is an alcohol, Butane does not have anything except Carbon and Hydrogen. I found this on google:

Hydrogen bonding in alcohols An alcohol is an organic molecule containing an -O-H group. Any molecule which has a hydrogen atom attached directly to an oxygen or a nitrogen is capable of hydrogen bonding. Such molecules will always have higher boiling points than similarly sized molecules which don't have an -O-H or an -N-H group. The hydrogen bonding makes the molecules "stickier", and more heat is necessary to separate them. Ethanol, CH3CH2-O-H, and methoxymethane, CH3-O-CH3, both have the same molecular formula, C2H6O.

---- Note: If you haven't done any organic chemistry yet, don't worry about the names.

----

They have the same number of electrons, and a similar length to the molecule. The van der Waals attractions (both dispersion forces and dipole-dipole attractions) in each will be much the same. However, ethanol has a hydrogen atom attached directly to an oxygen - and that oxygen still has exactly the same two lone pairs as in a water molecule. Hydrogen bonding can occur between ethanol molecules, although not as effectively as in water. The hydrogen bonding is limited by the fact that there is only one hydrogen in each ethanol molecule with sufficient + charge. In methoxymethane, the lone pairs on the oxygen are still there, but the hydrogens aren't sufficiently + for hydrogen bonds to form. Except in some rather unusual cases, the hydrogen atom has to be attached directly to the very electronegative element for hydrogen bonding to occur. The boiling points of ethanol and methoxymethane show the dramatic effect that the hydrogen bonding has on the stickiness of the ethanol molecules: ethanol (with hydrogen bonding) 78.5°C methoxymethane (without hydrogen bonding) -24.8°C The hydrogen bonding in the ethanol has lifted its boiling point about 100°C.

012
Molecular Mass

How does molecular mass effect boiling point?

For molecules of similar polarity, larger molecular masses would equate to higher boiling points. This is because molecules with larger masses would have stronger intermolecular van der Waals forces.

012
Chemistry
Atoms and Atomic Structure
Molecular Mass

How many moles of KCI would be dissolved in 4 liters of water to make a 2 Molar solution?

eight

91011
Chemistry
Atoms and Atomic Structure
Molecular Mass

Calculate the number of moles in 2400g of Co2?

54.54

567
Molecular Mass

What is the difference between formula mass and molecular mass?

The formula mass is used to express the mass of ionic compounds and molecular mass for the molecules or covalent compounds.

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