Properties
What property is tested by seeing if the substance dissolves in a liquid?
Solubility
To form a scientific argument, you need what 3 components?
A claim, evidence, and big ideas (key concepts)
________ of substances can help us identify what they are/differentiate between substances
Properties
Calcium chloride (CaCl2) can react with sodium hydroxide (NaOH). Which of the following could be a product of this reaction? Why?
a) CaOH (calcium hydroxide)
b) KCl (potassium chloride)
c) MgO (magnesium oxide)
Only CaOH because it has the atoms found in the reactants. The other two have atoms that are NOT found in the reactants, so they couldn't be produced.
What property is tested by lighting the substance on fire?
Flammability
Let's say you have the question: "What is the only gas that could be produced from the reaction of a bath bomb in water?"
What would be a reasonable claim statement?
The gas produced can only be carbon dioxide.
In a closed system, matter cannot exit so what stays the same? (this is also known as what law in science?)
Mass; law of conservation of mass
Molecules of vinegar (C2H4O2) and molecules of baking soda (NaHCO3) react, which of the following could be products of that reaction, and which could NOT be? How do you know?
a. Sodium chloride (NaCl)
b. Carbon dioxide (CO2)
c. Potassium iodide (KI)
Only CO2 because it has atoms are in the reactants. It CANNOT be NaCl because there is no chlorine (Cl) in the reactants) and it CANNOT be KI because there is no potassium (K) or iodine (I) in the reactants. According to the law of conservation of mass, the number and type of atoms in a chemical reaction stay the same; the atoms just rearrange
What property is defined as how tightly packed a substance is?
Density
What is this argument missing?
The bath bomb gas could only be nitrogen. Denser gases sink in less dense gases, so that's how we know.
Evidence to support the claim
If something is soluble in water, what does that mean?
Name a situation that you'd WANT a substance to be soluble, and name a situation where you'd NOT want a substance to be soluble.
It means it can dissolve in water.
We would want sugar to dissolve in water to have yummy lemonade.
We would NOT want concrete to dissolve in water or our roads would dissolve every time it rained.
Atoms of magnesium (Mg) and molecules of oxygen (O2) react, which of the following could be products of that reaction, and which could NOT be? How do you know?
a. Sodium chloride (NaCl)
b. Carbon dioxide (CO2)
c. Magnesium oxide (MgO)
Only MgO could be produced, as its atoms match the atoms in the reactants. The other two could NOT be produced because their atoms are not all in the reactants: no sodium or chlorine (to make sodium chloride) and no carbon (to make carbon dioxide)
An unknown solid dissolves in water. How does that help you figure out what substance it is?
Solubility is a property, so we can eliminate any substances that don't dissolve in water
What is this argument missing?
The bath bomb gas could only be argon, carbon dioxide, or nitrogen. When we investigated density, we found the BB gas is more dense than air. These 3 gases are also more dense than air.
Tying in a big idea to support the evidence
What do atoms do in a chemical reaction?
Atoms of the reactant molecules break apart and rejoin in new ways (i.e., rearrange) to form new product molecules
Draw how the molecules of hydrochloric acid (HCl) and sodium hydroxide (NaOH) would react at an atomic revel to produce H2O and NaCl.
Your diagram should show atoms of the reactants rearranging to produce those products.
An unknown gas is flammable. How could that help you determine what it is?
Because flammability is a property, so you could eliminate any nonflammable gases
How does state of matter help us to know that the gas produced by bath bombs is NOT originally in the bath bombs?
State of matter is a property. Since none of the starting ingredients in a BB are gases, that means the gas didn't originally exist in the bath bombs as a gas.
What are several signs of a chemical reaction, and WHY are they signs?
They are signs because they show the properties have changed, which indicates new substances have been formed. Example: light produced (change in flammability), new odor, unexpected color change, production of gas (change in state), or heat produced (when no heat added)