# 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
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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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?

This amount may be different because rust is not a clearly definite compound.

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Temperature
Molecular Mass

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

The density of air is 1.20 g/L. Use the mass formula (density x volume) to get your answer. 1.20 g/L x 5L equals 6g. mass=6g

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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.

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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

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Physics
Molecular Mass

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

Acceleration = Force/mass.

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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.

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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.

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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) 78.5Â°C methoxymethane (without hydrogen bonding) -24.8Â°C The hydrogen bonding in the ethanol has lifted its boiling point about 100Â°C.

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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.

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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?

We need 8 moles potassium chloride.

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Chemistry
Atoms and Atomic Structure
Molecular Mass

ca

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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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Chemistry
Atoms and Atomic Structure
Molecular Mass

# What is the mass of 5 moles of helium He atoms?

5 moles of helium He atoms is equivalent to 20,013 g.

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Chemistry
Atoms and Atomic Structure
Molecular Mass

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Molecular Mass

# What is the molecular formula of a compound with an empirical formula of CH and a molecular mass of 78?

CH = 13 so 78/13 = 6 The compound is C6H6 = benzene (most likely).

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Chemistry
Atoms and Atomic Structure
Molecular Mass

# How many moles are in 29.0 g of calcium?

29,0 g of calcium is equal to 0,723 moles.

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Molecular Mass

# What is the molar mass of Fe?

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Chemistry
Elements and Compounds
Molecular Mass

# What is the molecular formula of a compound with an empirical formula of C2OH4 and a molar mass of 88 grams per mole?

This compound may be dioxane - C4H8O2.

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Chemistry
Molecular Mass

# Why doesn't the mass change in a chemical reaction?

Actually the mass does change by exactly the amount that E = Mc**2 predicts. But in chemical reactions the change in mass is many orders of magnitude smaller than the accuracy of the best standard chemical balances. The change has been measured and verified on custom built ultraprecise balances, but such equipment is far beyond the budget of ordinary laboratories and unnecessary for their needs.

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Molecular Mass

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Kinematics
Molecular Mass

# What is the energy of molecules in motion?

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