Holy Moly 6.0-6.4

1. Which molecular formula is correctly paired with its corresponding empirical formula?

• 0. CO₂ and CO

• 0. C₂H₂ and CH₂

• 0. C₆H₆ and C₂H₂

• 0. P₄O₁₀ and P₂O₅

Answer explanation

EF = same elements in lowest ratio to eachother

MF reflects what one particular compound actually is so the amount of each element may may be greater

ex CH vs C₂H₂

1. What is the empirical formula for C₃H₆?

• 1. CH

• 1. CH₂

• 1. CH₃

• 1. CH₆

Answer explanation

Only one of these has:

the same elements in the lowest ratio AND has them in a ratio that can be multiplied by one common number to get the given compound

CH₂ can be multiplied by 3 to get C₃H₆

the given compound is a multiple of the ef!

1. What is the empirical formula for the compound C₆H₁₂O₆?

• CH₂O

• C₂H₄O₂

• C₃H₆O₃

• C₆H₁₂O₆

4. The formula H₂O₂ is an example of

5. Hint: To see if it's an EF, ask yourself: Are the elements in the lowest ratio possible to each other?

6. (Meaning, is there any number you can divide both of them by and still get a whole number for each? )

• molecular formula

• empirical formula

• ionic formula

• organic formula

Answer explanation

1. H₂O₂ can be divided by 2 to get HO

2. 2/2 =1 and 2/2 = 1

4. side note, to be organic something must contain a C bound to H

4. What is the gram formula mass of Na₂CO₃ • 10H₂O?

6. *GRAM FORMULA MASS (g/mol) = MOLAR MASS (g/mol)

• 106 g/mol

• 142 g/mol

• 266 g/mol

• 286 g/mol

Answer explanation

Side note: Sometimes, at least in the pass, they just put g in the answers. It's understood the gram amount is in reference to 1 mol of the substance.

What is the gram formula mass of Li₂SO₄?

• 54 g/mol

• 55 g/mol

• 110 g/mol

• 206 g/mol

Answer explanation

side note: sometimes they just put g in some answers as it's understood it's the amount of grams in reference to 1 mol of substance

What is the formula mass of Li₂SO₄?

• 54 g/mol

• 54 amu

• 55 g/mol

• 110 g/mol

• 110 u

Answer explanation

just plain old formula mass = amu or u

11. Which substance has the greatest molecular mass?

• I₂

• H₂O₂

• CF₄

• NO

11. Which represents the greatest mass of chlorine?

• 1 atom of chlorine

• 0. 1 mole of chlorine

• 1 molecule of chlorine

• 1 gram of chlorine

Answer explanation

ignore the rounding & dots under the given, it's hard to make a picket fence on this :)

Chlorine exists as a diatomic, Cl₂

1 atom of Cl | 1 mol Cl ........| | 35 g Cl |

.................. | 6.02 x 10²³ atoms | 1 mol Cl

1 molec Cl₂ | 1 mol Cl₂ .... .... | 71 g Cl₂

_{...........................}|6.02 x 10²³ molec | 1 mol Cl₂

1 g Cl₂ x (1 mol Cl₂ / 71 g Cl₂)

Tags

NGSS.HS-PS1-7

What is the total number of atoms of oxygen in the formula Al(ClO₃)₃ • 6H₂O?

• 6

• 9

• 10

• 15

Answer explanation

Al(ClO₃)₃ • 6H₂O?

Aluminum Chlorate Hydrate

Aluminum Chlorate part contributes 9 oxygen

the hydrate part contributes 6 oxygen