Coefficients, Parenthesis, & Subscripts

Multiple Choice

Which table correctly labels the parts of the atomic model?

Multiple Choice

The graph shows the phases of water at different temperatures and pressures with four water samples marked. Which change to a water sample will cause a phase change?

• Increase the pressure of sample 1 to 100 atm.

• Decrease the temperature of sample 2 to 0°C.

• Increase the pressure of sample 3 to 1 atm.

• Decrease the temperature of sample 4 to 100°C.

Open Ended

In your own words, describe what a subscripts is or does when it comes after an element.

Multiple Choice

C₆H₁₂O₆ means I have __C (Carbon),__H (Hydrogen), and __O (Oxygen).

• 6,6,6

• 6,12,18

• 6,12,6

Fill in the Blank

Na₂Cl₃, means I have __Na.

Open Ended

In your own words, describe what a coefficient is or does to the chemical formula it is in front of.

Multiple Choice

2NaCl, means I have _Na and _Cl.

• 2,2

• 1,1

• 1,2

• 2,1

Multiple Choice

2 H₂O means I have _molecules (groups) of H₂O.

• 1

• 2

• 3

• 4

Parenthesis

Remember PEMDAS

Now that we have learned how to count subscripts and coefficients, we are moving on to parenthesis.

PEMDAS is used to remember that in math you work a problem by it's Parenthesis first, then it's exponents, multiplication/division, and finally addition/subtraction.

​Multiply the subscript that is outside the parenthesis by the number of atoms that are inside the parenthesis.

Parenthesis

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Putting it all together...

Coefficients, subscripts, and parenthesis:

Since we have went over how completing the parenthesis works, we need to finally put all 3 of these together before moving forward.
Parenthesis will always be completed first according to PEMDAS, and that is what you need to remember most.
Once you work the parenthesis, you then work the coefficient.
Always check for a subscript.

Multiple Choice

 (H₂O)_{3, means there are how many H atoms and O atoms?}

• H6, O3

• H2, O1

• H2, O3

Multiple Choice

 (C₆H₁₂O₆)_{4, means there are how many atoms of each element total?}

• C6, H12, O6

• C24, H48, O24

Multiple Choice

 Ca(ClO₂)_{2, means there are how many atoms of calcium (Ca)?}

• 1

• 2

Multiple Choice

Co(NO₃)_{2, means there are how many atoms of cobalt (Co)?}

• 1

• 2

• 3

Multiple Choice

Co₄ (NO₃)₂, means there are how many atoms of cobalt (Co)?

• 1

• 2

• 3

• 4

Multiple Choice

3NaHCO_{3, means there are how many atoms of Oxygen?}

• 1

• 3

• 6

• 9

Multiple Choice

 8C₃H₈O, means there are how many atoms of Oxygen (O)?

• 1

• 3

• 8

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