Science Study

martiniho's version from 2016-11-03 07:11

Section 1

Question Answer
Elementa pure substance consisting entirely of one pure atom
Atomthe fundamental building blocks that everything is made of.
Sub atomic particlesneutrons, electrons and protons
Atomic Weight vs Atomic MassAtomic mass is generally the smaller number, how many protons and electrons a substance has. Atomic Weight is the average of weight of particles in all isotopes.
Element, compound and mixtureelement is a pure substance made from one particle, compound is a substance with two more more bonded atoms, mixture is a substance mixed together and not chemically bonded.
Changes of statessold melts into a liquid, and boils into a gas, condenses into a liquid and solidifies into a solid.
Densitymass/volume, the amount of matter inside a volume, determines which substance is heavier.
Physical Changewhen a substance changes state from solid, liquid or gas. No new substances are made, they can be separated into
Chemical Changewhen a new substance is made from two reactants, it forms new bonds and makes a new substance, it can be said when: temperature, color changes, precipitation, explosions etc.
DiffusionIt occurs when a substance equally spreads out from a high to low concentration throughout another substance.
Significance of Bondswithout them, no new substance can be made, substances exist because of them, energy is stored in them.
Metalslocated on the left side of the periodic table, dense, lustrous, malleable, ductile, high melting and boiling points etc.
Non-metalslocated on right side of zig-zag, dull, brittle, low melting + boiling points,
alloysconsist of base metal + additional materials to make a product better than the original.

Section 2

Question Answer
Mixingwhen a substance goes into another without chemically changing, it can be separated again.
Chemical Reactiona new substance is made, new chemical bonds. ex=precipitation, change in colour/temp, explosions, gas etc.

Section 3

Question Answer
Exothermica reaction that releases heat
Endothermica reaction that absorbs heat
simple word formulas for chemical reactionslol = Carbon + Oxygen ------> co2
3. factors that affect rate of reactionthe concentration of particles. more particles in a certain volume=more contact= faster reaction
1. factors that affect rate of reactionsize of particles, smaller particles=more surface area= more contact= more reaction speed
4. factors that affect rate of reactionpresence of catalysts. speed up rate of reaction, living biological catalyst. they are not reactants.
2. factors that affect rate of reactiontemperature, more kinetic energy=more movement=more collisions=sped up reaction