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School > Chemistry Test - Moles > Flashcards

Chemistry Test - Moles Flashcards

1
Q

A mole is like…

A

a dozen

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2
Q

A dozen donuts?

A

12

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3
Q

A mole is how many hexillion?

A

602 hexillion

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4
Q

A mole of cars is how many?

A

A mole of cars is 602 hexillion

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5
Q

Avocados number is the mole but what is it?

A

6.02x10^23

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6
Q

Molar mass is what?

A

The mass of one mole

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7
Q

To calculate the molar mass of a compound..

A

you need to determine the atomic masses of the elements present in the compound and then sum them up based on the molecular formula

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8
Q

Step by step for Molar Mass:

A
  1. Identify the molecular formula of the compound. For example, let’s use water (H2O) as an example.
  2. Determine the atomic masses of the elements. You can find the atomic masses of elements on the periodic table. The atomic mass represents the average mass of an atom of that element. For water (H2O), the atomic masses are:
    - Hydrogen (H): 1.008 g/mol (approx.)
    - Oxygen (O): 16.00 g/mol (approx.)
  3. Count the number of atoms of each element in the molecular formula. In water (H2O), there are two hydrogen atoms and one oxygen atom.
  4. Multiply the atomic mass of each element by the number of atoms present in the molecular formula.
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9
Q

Molar Mass Hydrates

A

The wet and the dry make the hydrate
The molar mass of dry powder plus molar mass of water
Subtract the two

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10
Q

Converting from mass to moles:

A

Moles = Mass / Molar mass
To convert mass (in grams) to moles, divide the given mass by the molar mass of the substance. The molar mass is the mass of one mole of the substance and is expressed in grams/mole.

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11
Q

Converting from moles to mass:

A

Mass = Moles x Molar mass
To convert moles to mass, multiply the given number of moles by the molar mass of the substance. The result will be in grams.

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12
Q

Converting from moles to the number of particles:

A

Number of particles = Moles x Avogadro’s constant
To convert moles to the number of particles, multiply the given number of moles by Avogadro’s constant (6.022 × 10^23 particles/mol). This will give you the number of atoms, molecules, or ions.

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13
Q

Converting from the number of particles to moles:

A

Moles = Number of particles / Avogadro’s constant
To convert the number of particles to moles, divide the given number of particles by Avogadro’s constant (6.022 × 10^23 particles/mol).

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14
Q

Calculating the Amount (Moles) from mass

A

To calculate the amount of moles from mass, you need to use the formula:

Moles = Mass / Molar mass
Here’s a step-by-step guide on how to calculate moles from mass:

  1. Identify the mass of the substance for which you want to calculate the moles. Make sure the mass is given in grams.
  2. Determine the molar mass of the substance. The molar mass is the mass of one mole of the substance and is expressed in grams/mole. You can find the molar mass by adding up the atomic masses of the elements present in the substance based on its chemical formula. The molar mass values can be found on the periodic table.
  3. Divide the given mass by the molar mass to calculate the amount of moles. Make sure the units cancel out properly. The resulting value will be in moles.
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15
Q

Calculating Mass from Amount (Moles)

A

To calculate the mass from the amount of substance given in moles, you need to use the concept of molar mass. The molar mass represents the mass of one mole of a substance and is expressed in grams per mole (g/mol).

Here’s the formula for calculating the mass from moles:

Mass (in grams) = Moles × Molar Mass

To use this formula, you’ll need to know the number of moles and the molar mass of the substance you’re interested in. The molar mass can be determined by adding up the atomic masses of all the atoms present in a molecule.

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16
Q

Percent Composition: Lab Data Steps

A
  1. Identify masses
  2. Calculate the percent composition (% comp = m element/sample x 100)
  3. Do it for each element
  4. Should add to 100% - CHECK IT
17
Q

Percent Composition: Formula Steps

A
  1. ASSUME 1 MOLE
  2. Calculate the Molar Mass for each element
  3. Calculate the molar mass for the whole formula (add the molar masses and multiply)
  4. The molar mass is also mass (grams) because its one mole - show that line
  5. Calculate the percent composition (% comp = molar mass aka mass /total mass x 100)
  6. Do it for each element
  7. Should add to 100% - CHECK IT
18
Q

Empirical formula:

A

lowest whole number ratio of the elements in the compound

19
Q

To find the empirical formula from the percent composition, you need to follow these steps

A

To find the empirical formula from the percent composition, you need to follow these steps:
1. Assume you have a 100g sample of the compound.
2. Convert the percent composition of each element into grams.
3. Convert the grams of each element into moles by dividing the grams by the molar mass of that element. 4. Find the mole ratio by dividing each element’s mole value by the smallest mole value obtained in step 3.
5. If the mole ratios obtained in step 4 are not whole numbers, multiply all ratios by the smallest number that will convert them into whole numbers.

20
Q

Molecular formula:

A

a chemical formula that shows the number of different atoms present in a molecule.

21
Q

Here are the steps to determine the molecular formula from percent composition:

A
  1. Assume you have a 100g sample of the compound.
  2. Convert the percent composition of each element into grams.
  3. Convert the grams of each element into moles by dividing the grams by the molar mass of that element. The molar mass can be found on the periodic table.
  4. Find the mole ratio by dividing each element’s mole value by the smallest mole value obtained in step 3.
  5. If the mole ratios obtained in step 4 are not whole numbers, multiply all ratios by the smallest number that will convert them into whole numbers.
  6. Determine the empirical formula using the mole ratios found in step 5.
  7. Determine the molar mass of the empirical formula.
  8. Divide the given molar mass of the compound by the molar mass of the empirical formula obtained in step 7.
  9. Multiply the subscripts in the empirical formula by the value obtained in step 8. This will give you the molecular formula.
22
Q

mass but with avacado and particles

A

To calculate the mass of 0.52 x 10^23 particles of CoCl2, we need to use the following formula:

mass = number of particles x molar mass / Avogadro’s number

The molar mass of CoCl2 is approximately 129.83 g/mol, and Avogadro’s number is approximately 6.022 x 10^23 particles/mol. Substituting these values and the given number of particles into the formula, we get:

mass = 0.52 x 10^23 x 129.83 g/mol / 6.022 x 10^23 particles/mol
mass = 11.2 g

Therefore, the mass of 0.52 x 10^23 particles of CoCl2 is approximately 11.2 grams.

23
Q

mass with avocado and particles

A

mass = number of particles x molar mass / Avogadro’s number

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