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Matter Lab 6-8 / Week 06 / Friday
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Week 06 · Atoms Team Up: Molecules

Friday

Molecules all around you
// The recipe for a substance
⏱ about 20 min

Friday: Molecules All Around You

Rocket breathes on the kitchen window and watches the fog spread. "Water molecules," he says. "From me."

Raven holds up a glass of fizzy water. Bubbles climb the sides. "And what do you notice in here?"

"Carbon dioxide," Rocket says. "CO2, dissolved in water. A solute in a solvent, like last week."

Nova hovers over the salt shaker. "And this?" she asks. "Molecule or pattern?"

"Pattern," Rocket says. "Sodium, chlorine, sodium, chlorine, forever."

Raven writes three formulas in the Bench Log: H2O, CO2, NaCl. "Breakfast, in chemistry."

"Everything is made of something," Rocket says, "and now I know the recipes." Nova's light brightens. "Time to review."

Three substances you meet every day

Water is H2O, two hydrogen atoms and one oxygen atom. It is in your breath, your glass and the air as vapor.

Carbon dioxide is CO2, one carbon atom and two oxygen atoms. It is the gas that dissolves in water to make fizzy water.

Table salt is sodium chloride, NaCl, an extended structure of sodium and chlorine in equal parts. Water molecules pull those parts apart when salt dissolves.

The air itself is a mixture, mostly nitrogen and oxygen, each as a two-atom molecule.

SubstanceFormulaMolecule or extended structure?Where you meet it
WaterH2Omoleculebreath, glass, vapor in the air
Carbon dioxideCO2moleculebubbles in fizzy water
Oxygen gasO2moleculethe air
Table saltNaClextended structurethe salt shaker
MOLECULES IN THE KITCHEN
  • Read the question.
  • Tap your answer.
The bubbles in fizzy water are which substance?
Which everyday substance is an extended structure rather than a molecule?
When salt dissolves, what pulls the sodium and chlorine parts away from each other?

Why the recipe matters

This week's standard asks you to model the atomic composition of simple molecules and extended structures. Your bean models did exactly that.

The same kinds of atoms in a different count make a different substance: H2O and H2O2, or O2 and O3.

Next week you will watch substances change. Some changes keep the molecules the same, and some rearrange the atoms into new ones.

When you see fizzing, a color change or a new solid next week, ask yourself: did the recipe change?

Week reviewTrue or false?
All matter is made from atoms.?
A water molecule has two oxygen atoms.?
The small number after a symbol tells how many atoms of that element.?
Table salt is made of separate molecules.?
The atomic number is the number of protons in each atom of an element.?
WHY THIS EXERCISEThese five ideas are the whole week: atoms, molecules, formulas, crystals and the periodic table.
OUR WEEK, IN ORDER
  • ?We read formulas as recipes and compared H2O with H2O2.
  • ?We learned that all matter is made from atoms and built a water molecule.
  • ?We built five molecule models and a salt crystal pattern.
  • ?We found water, carbon dioxide and salt in the kitchen.
  • ?We read atomic numbers from the periodic table.
WHY THIS EXERCISEThe week moved from three beans on the Bench to the list of every kind of atom.
The formula for carbon dioxide is ____.
The formula for table salt is ____.
How many atoms are in one molecule of carbon dioxide? Type a number.
WHY THIS EXERCISECounting atoms in a formula is the skill next week's reactions build on.
Try it
Look at the ingredient list on a box of table salt or a bottle of water. Which substances from this week do you find?
Write their formulas in your Bench Log.
Draw your kitchen with three labels: H2O on the glass of water, CO2 on the fizzy bubbles, NaCl on the salt shaker.

Strong week, chemist. Tomorrow is Bench Day: your family builds the biggest molecule set the Bench has ever seen.

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