Chemistry Chapter 6 Flashcards
Physical Change.
A change which does not alter the chemical composition of a substance.
-change, = chemical composition
In general, which is easier to reverse: physical or chemical changes?
Physical changes are fairly easy to reverse, while chemical changes are much harder or impossible to reverse.
What is the most common unit for measuring temperature change?
Celcius
What are the two reference points used in the creation of the temperature scale?
Freezing = 0 C (32 F)
Boiling = 100 (212 F)
How do you convert degrees Celsius to degrees Fahrenheit?
Degrees F = 9/5 (degrees C) + 32
What type of change is phase change?
Physical
What are the four phase changes and which 3 apply to chemistry mose?
Solid, liquid, gas + plasma
Solid to liquid =
Melting
Liquid to gas
Vaporizing
Gas to liquid
Condensing
Liquid to solid
Freezing
Solid to gas
Sublimation
Is volume additive?
Not necessarily because there is space between the molecules that make up any substance; mixing the two molecules squeezes some of that space.
Is mass additive?
Yes.
Kinetic Theory of Matter
The molecules (atoms) that make up a substance have space in between them, and they are in constant, random motion. The hotter the substance, the faster the motion.
Explain the heating curve.
Temperature stays constant until a phase change is completed. E.g. ice is below 0 degrees, goes to 0 degrees when melting, when melting completed, temperature increase to 100 degrees. Stays at 100 degrees until evaporation completed. Water vapour can then be heated to higher temperature.
How are the phases of water exceptional?
Kinetic phase — substance take up the least amount of volume in solid, then liquid and most volume in gas. Water is different — solid has a little bit more space between molecules than liquid at a similar temperature.
Put the three major phases (solid, liquid, gas) in order of least volume to greatest volume according kinetic theory of matter for most substances.
Solid — liquid — gas
Why is it important that water’s phases are exceptional to the kinetic theory of matter?
Otherwise ice would float on top of lakes and would not insulate lakes to allow aquatic life to survive the winter.
What happens to atoms during chemical reactions?
They get rearranged and form new chemicals.
What are the phase symbols used in chemical equations for the three most common phases?
Solid (a); liquid (l); gas (g)
`In a chemical equation, what is on the left side of the arrow? The right?
Left = reactants; right = products
What is a balanced chemical equation? How do you do this?
Number of reactant atoms is equal to number of product atoms. When balancing a chemical equation, you can change the numbers of the left of the molecules as much as you want. You just can’t change the subscripts in the chemical formulas. —> change number of molecules, not subscripts.
What is a homonuclear diatomic? What are the seven examples?
