Matter and Scientific Method
What is Matter?
Anything that has Volume and Mass
What is the difference between elements and compounds?
Elements are made of one type of atom and can not be broken down, whereas Compounds are made of two or more elements that are chemically bonded.
Which state of matter has a highest energy?
Gases
What are chemical properties?
The Ability of a substance to undergo a chemical reaction
In the reaction 2H₂ + O₂ → 2H₂O, identify the reactants and products.
2H₂ + O₂ are the Reactants
2H₂O are the Products
What are the three categories we classify Matter into?
Elements, Compounds and Mixtures
Why is salt water considered a homogeneous mixture while oil and water is heterogeneous?
Salt dissolves evenly, oil and water separate into layers
Which state of matter has the lowest forces of attraction between its particles?
Gases
Given an example of a physical property
mass, volume, density, color, malleability, ductility, ability to dissolve
During a chemical change, what specifically happens to the bonds between atoms?
Bonds break and new bonds form
What is an Atom?
The smallest unit of an element (matter)
Explain why carbon dioxide (CO₂) is a compound but air is a mixture?
CO₂ has chemically bonded atoms, air is different gases physically mixed.
If you double the temperature of a gas, what happens to the average kinetic energy of its particles?
It doubles
Which is an intensive property—mass or density? Explain why.
Density - does not change based on amount of matter
What is the Law of Conservation of Mass?
Matter cannot be created or destroyed, only transformed
What State of Matter has a definite Shape and Volume?
Solids
What is one difference between an Compound and Mixture?
Compounds are chemically bonded and mixtures are physically bonded.
or
Compounds have a fixed composition and mixtures have a varied composition
What would happen to the average kinetic energy if the temperature decreased?
Average kinetic energy would decrease (particles would slow down).
What is the difference between intensive and extensive properties?
Intensive properties do not depend on the amount of matter
Extensive properties do depend on the amount of matter
What are some indicators of chemical changes (chemical reactions)?
Energy change (heat, light)
Production of gas
Change in color
Formation of a precipitate
Why is it important to only change one independent variable at a time in an experiment?
So you know exactly what caused the change in the dependent variable.
What is CH₃NH₂ classified as?
Compound
Liquids can flow while solids cannot. Which two KMT assumptions explain this difference?
Particles are in constant motion + particles have spaces between them
What is one example of a chemical change
Burning, rusting, reacting with water, tarnishing
A student burns magnesium in oxygen and measures the mass of the product. The mass is greater than the original magnesium. How does this agree with the Law of Conservation of Mass?
Oxygen from the air combined with magnesium, so the total mass of reactants = total mass of products