問題一覧
1
Gases
(no definite volume nor shape)
2
Chemical change
changes the identity of the substance( wood burning to form ashes and smoke)
3
Liquids
(definite volume but no define shape)
4
Heterogeneous mixture
mixtures of unevenly distributed substances (can tell it is a mixture)
5
Exothermic
releases heat energy
6
Kinetic energy
the energy of motion
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Observation
carefully noting and recording changes during an experiment
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Nuclear theory of the atom
•electrons orbit the nucleus •nuclear forces hold the nucleus together •nucleus determines atomic identity
9
Homogeneous mixture
mixtures of evenly distributed substances (cannot tell it is a mixture)
10
Endothermic
absorbs heat energy
11
Compound
a molecule that is made of 2 or more elements
12
What is an ion
when a neutral atom (no charge) gains or loses electrons
13
Element
made of one type of atoms
14
Daltons atomic theory
•the atoms of each element are unique •atoms are unchanged in chemical reactions
15
Solids
(definite volume and shape)
16
3 main types of radioactive decay
•alpha particles •beta particles •gamma rays
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Potential energy
energy that is stored
18
A law
describe a consistent, observable relationship in nature, based on repeated experimental observations
19
A theory
provides a coherent and comprehensive understanding of a set of phenomena or observations
20
Physical change
changes that don’t change the identity of the substance except color chnage ( an ice cube(solid)melts to water(liquid))
21
Matter is
anything that has mass and take up space including liquids