Subscripts and Bath Bombs

Multiple Choice

A student studies a sample of granite and finds that it is mostly made of four minerals. The minerals are potassium feldspar (KAlSi₃O₈), sodium plagioclase (NaAlSi₃O₈), calcium plagioclase (CaAl₂Si₂O₈), and quartz (SiO₂). The minerals are visible crystals in the granite.

Which table correctly sorts the elemental and compound molecules in granite?

Multiple Choice

Polylactic acid, or PLA, is one type of material used in many 3D printers. Unlike other plastics, PLA is made by combining starch from a plant with lactic acid produced by bacteria. The lactic acid and starch go through several chemical processes under high temperatures, changing the structures of both the starch and lactic acid into PLA.

PLA is being investigated for its use in medical implants, such as screws that hold tendons to bone following injuries. PLA breaks down into starch and lactic acid between 6 months and 2 years, and both are used by the body.

What is the benefit of PLA over traditional plastics?

• It can break down into substances used by the body.

• It can be used to secure tendons to bone.

• It can be implanted inside the body.

• It can be printed into any shape.

10/4/2024 - Identifying Elements & Counting Atoms

​We have learned that there are 118 elements on the periodic table of elements. Out of those 118, we usually only stick with the first 18 of them in middle school.

Do you remember our marshmallow lab?

Marshmallow Lab

We worked through this lab my using molecules or groups of elements or compounds to figure out how many atoms of each element there were.

Ex: H₂O ----> Hydrogen: 2 Oxygen: 1 (There is no number after oxygen, therefore it is only 1 atom of oxygen.)

Subscripts

The subscript tells you the number of atoms of a particular element and only refers to the element that it is behind. If there is no subscript, there is only one atom of that element.

Example: CaCl_{2
Calcium =} 1 _{atom
Chlorine =} 2 _atoms

Multiple Choice

How many atoms of Li are there in the chemical formula:

Li₂SO₄

• 1

• 2

• 3

• 4

Multiple Choice

How many atoms of O are there in the chemical formula: Li₂SO₄?

• 1

• 2

• 3

• 4

Multiple Choice

How many atoms of C are there in the chemical formula: CH₃CO₂

• 1

• 2

• 3

• 4

Mrs. Moore

• Subscripts are small numbers after the symbol of an element. For example, the 2 in O2 is a subscript. 

• Subscripts tell you how many atoms of that element there are. For examples there are 2 oxygen atoms in O2

• If there is no subscript after an element, it means that there is just one atom of that element

Multiple Choice

 F₂  means there are _____ atoms of fluorine

• 1

• 2

• 3

• 4

Multiple Choice

C₄  There are _____ atoms of carbon

• 6
• 2
• 4
• 8

Multiple Choice

H₃  There are ______ atoms of hydrogen

• 3
• 5
• 4
• 2

Multiple Choice

S  There are _____ atoms of sulfur

• no

• 1

• 2

• 3

Let's try some harder problems.

Dropdown

H2O means there are ​ ​

Select answer

Hydrogen and ​

Select answer

Oxygen.

Dropdown

C₃H₈O means that there are ​

Select answer

Carbon, ​

Select answer

Hydrogen, & ​

Select answer

Oxygen atoms.

Dropdown

C₆H₁₂O₆, means that there are ​

Select answer

carbon atoms, ​

Select answer

Hydrogen atoms, & ​

Select answer

Oxygen atoms.

Dropdown

NaHCO₃, means that there are ​

Select answer

atoms of Sodium (Na), ​

Select answer

atoms of Hydrogen, ​

Select answer

atoms of Carbon, and ​

Select answer

atoms of Oxygen.

Bath Bombs

Bath bombs can come in all types of shapes, sizes, and festive colors, depending on the molds and dyes used. They can also have a wide range of ingredients, including bath salts, various fragrances, and other components. That said, there are a few key ingredients that most simple bath bomb recipes have: baking soda, citric acid, and cornstarch. When baking soda and citric acid are mixed together with some water, they undergo a chemical reaction. Specifically, this reaction involves acid-base chemistry, since the baking soda—also known as sodium bicarbonate (NaHCO₃)—is a weak base, and citric acid (C₆H₈O₇) is a weak acid. This reaction is shown in Equation 1, on the next slide. As you can see from Equation 1, the acid-base reaction produces carbon dioxide (CO₂) gas. This gas is what makes the fizzy bubbles when you toss a bath bomb into a tub full of water.

Equation 1:

Na₃HCO₃ + C₆H₆O₇ ---> CO₂ + H₂O + Na₃C₆H₅O₇

The above equation is read as the reactants on the left side of the arrow (what goes in) and the product is on the right side of the arrow (what comes out/is produced). Any time you have a chemical equation such as the above, you must make sure to check to make sure it is balanced.

Dropdown

Na₃HCO₃ + C₆H₆O₇ , the reactant side, has ​

Select answer

Sodium (Na), ​

Select answer

Hydrogen (H), ​

Select answer

Carbon (C), & ​

Select answer

Oxygen (O).

Dropdown

CO₂ + H₂O + Na₃C₆H₅O_7, the product side, has ​

Select answer

Carbon (C), ​

Select answer

Oxygen (O), ​

Select answer

Hydrogen (H), and ​

Select answer

Sodium (Na).

Dropdown

After the last two equations (Reactant and Product), we should be able to conclude that Na₃HCO₃ + C₆H₆O₇ ---> CO₂ + H₂O + Na₃C₆H₅O_{7 is a} ​

Select answer

equation, and it follows the Law of Conservation of Mass, which states that mass is neither ​

Select answer

nor ​

Select answer

in a chemical reaction.

Now it is time to make us some bath bombs!
I have provided everything you need. Only choice you will need to make, is if you want to add color (food dye) and if you want it to have essential oils in it or not.

I have 3 essential oils with me today.
1. Peppermint Oil: used for headaches, muscle aches, joint pain & itching.
2. Eucalyptus Oil: relieves congestion and helps with muscle and joint pains.
3. Tea Tree Oil: helps fight bacteria (great for acne)

Ingredients:

·   1 cup citric acid

·   1 ½ cups baking soda

·   ½ cup almond oil or coconut oil

·   8-10 drops essential oils

·   silicon mold or ice cube tray

Directions:

1.       In a medium bowl, whisk together the citric acid and baking soda. With a spoon or spatula, mix in almond oil and essential oils. Mixture should just hold together when pressed between fingers.

2.       Press mixture into your molds so that it’s firmly packed. Let dry for 24 hours. If bombs don’t yet hold together, let dry longer.