physics and chemical Flashcards
(82 cards)
1
Q
energy
A
produces change in a system. there are different forms of it. it can be transferred or transformed. physical quantities contribute to different forms of energy.
2
Q
difference between system and surroundings
A
system - anything under observation, defined by observer. surroundings - anything that is not part of a system.
3
Q
universe =
A
system + surroundings
4
Q
difference between kinetic and potential energy
A
kinetic - energy of motion potential - stored energy of an object as a result of its condition or position
5
Q
mechanical kinetic energy
A
energy of an object in motion
6
Q
radiant energy
A
energy of electromagnetic waves from an energy source
7
Q
thermal energy
A
energy of random motion of particles in a substance
8
Q
sound energy
A
energy of vibrations of particles
9
Q
electrical kinetic energy
A
energy of electrons moving along a wire
10
Q
chemical potential energy
A
energy stored in chemical bonds
11
Q
elastic potential energy
A
energy stored in a stretched or compressed object
12
Q
gravitational potential energy
A
energy due to the position of an object
13
Q
nuclear energy
A
energy stored in the nucleus of an atom
14
Q
electrical potential energy
A
energy is stored by a separation of positive and negative charges
15
Q
magnetic potential energy
A
energy stored in a magnetic field
16
Q
law of conservation of energy
A
law stating that energy is neither made or destroyed but is transformed from one form of energy to another or transferred from one object to another
17
Q
differences and similarities of energy transfers and transformations
A
transformation converts energy while transfer doesn’t, but they both obey law of conservation of energy
18
Q
differences between open, closed, and isolated systems
A
open - system can exchange both energy and matter with its surroundings. closed - system that can exchange only energy but not matter with its surroundings. isolated - system that cannot exchange energy nor matter with its surroundings
19
Q
equation for mechanical kinetic energy (KE)
A
Ek = 1/2mv2. Ek = mechanical kinetic energy (joules or J) m = mass (kg or kilograms) v = velocity (m/s or metres per second)
20
Q
equation for gravitational potential energy (GPE)
A
Eg = mg(delta)h Eg = gravitational potential energy (Joules or J) m = mass (kg or kilograms) g = acceleration due to gravity (9.8 metres per second squared) h = height (metres or m)
21
Q
give everyday examples of how energy is transformed in chemical reactions
A
cellular respiration - chemical potential energy in glucose bonds are used to make ATP (energy molecules). used in all reactions of living tissues. photosynthesis - plants and algae capture the sun’s energy and combine CO2 and H2O to produce glucose (sugar) and oxygen. fuel cells - transform chemical energy into electrical energy and emit fewer pollutants that fossil fuels.
22
Q
equation for combustion of methane
A
CH4 + 2O2 yields CO2 + 2H2O
23
Q
cellular respiration
A
all plants and animals carry out this to produce energy in the form of ATP (adenosine triphosphate) for life processes. C6H12O6 + 6O2 yields 6CO2 + 6H20 + energy. it happens in all reactions of living tissues and it it is what produces energy.
24
Q
photosynthesis
A
carbon dioxide and water combine with the addition of light energy, in a series of reactions to produce glucose and oxygen. 6CO2 + 6H2O + energy yields C6H12O6 + 6O2. it occurs in chloroplasts. the glucose created is used in cellular respiration.
25
fossil fuels
contain large amounts of chemical potential energy that was transformed from solar energy by ancient plants. the plants become buried under the right conditions to form these fuels.
26
what happens during combustion of fossil fuels
when fossil fuels are burned through combustion, energy is released along with carbon dioxide. fossil fuels also contain contaminants such as sulfur and nitrogen that pollute the environment.
27
why should we invest more money into researching fuel cells
because they transform chemical energy into electrical energy and emit fewer pollutants
28
alpha decay
nuclear reaction that emits alpha particles or helium nuclei. new nucleus has 2 fewer protons and 2 fewer neutrons. therefore, its mass number is reduced by 4 and its atomic number is reduced by 2.
29
mass number
number of protons plus neutrons in man atomic nucleus
30
atomic number
number of protons alone.
31
beta decay
nuclear reaction that emits beta particles or fast-moving electrons. new nucleus has one less neutron and one more proton.
32
gamma decay
nuclear reaction that emits gamma rays or high-energy photons. unstable isotope that is undergoing the decay has a "*" to represent an excited state.
33
differences and similarities between fission and fusion
both nuclear reactions produce much energy. fission - big nuclei breaks down into 2 smaller. fusion - 2 smaller nuclei combine into one big one.
34
nuclear fission and equations for these reactions
heavier nucleus splits into smaller, lighter nuclei with the release of energy. occurs in nuclear reactors. single fission usually results in chain reaction of many further reactions.
35
fission chain reaction
single reaction causes many further reactions. for nuclear fission, chain reaction results in the fission of many uranium-235 nuclei, dramatically increasing the amount of energy transformed.
36
nuclear reactor
transform thermal energy produced in nuclear fission into electrical energy
37
nuclear fusion and equations for these reactions
two very small nuclei combine, or fuse, to form a slightly larger nucleus. requires high temperatures, occurs in the sun and other stars, and does not produce radioactive material. energy released per unit mass is much larger for nuclear fusion then for nuclear fission.
38
absorption and chlorophyll
chlorophyll, the green pigment in plants, absorbs light. absorption is a process in which energy is taken up by matter without being reflected or transmitted. so chlorophyll is involved in the absorption process.
39
photovoltaic cells
transform light energy into electrical energy
40
vision and transformation of light energy
rods and cones in the retina of the eye absorb light energy. an electrical signal is sent to the brain by nerve cells and an image is formed.
41
3 types of energy that contribute to our earth's system
solar energy (has greatest impact on Earth), nuclear energy (transformed into thermal energy inside Earth's crust), and gravitational potential energy (used to produce electricity)
42
explain energy diagram for earth
100 percent incoming solar energy comes in, 31 percent is outgoing solar energy due to reflection, and 69 percent is outgoing infrared radiation, due to absorption by clouds and atmosphere, infrared radiation, latent and sensible heat. so 100 percent goes in, 100 percent goes out.
43
greenhouse gases
they warm earth's atmosphere and contribute to the greenhouse effect. they include carbon dioxide, water vapour, nitrous oxide, and methane
44
conduction and convection effects on earth's surface
conduction heats the air through collisions between molecules in the surface and in the air. convection moves warm air from close to the surface upward and cool air from higher in the atmosphere downward.
45
energy transformation and the water cycle
water vapour rising gains GPE. . condensation process releases thermal energy as the water vapour cools and condenses around atmospheric particles. clouds are formed. water precipitates, GPE transforming to MKE. thermal energy is transferred to atmosphere as precipitation falls. plants take up water from ground, or bodies of water. transpiration moves thermal energy into atmosphere. when water absorbs sun's energy, molecules move faster as solar energy is transformed to thermal. when enough energy is transformed, water evaporates. enters atmosphere as water vapour, bringing thermal energy with it.
46
specific heat capacity
the amount of energy required to change the temperature of 1 g of a substance by 1 degree celsius
47
climate change and aquatic/terrestrial ecosystems
because the water temperature is increasing, many species have to move to cooler waters, also affecting the animals relying on the moving aquatic animals such as tufted puffins. terrestrial ecosystems are negatively impacted by increase in radiation exposure. radioactive materials and wastes that accumulate in the soil are contaminating terrestrial ecosystems. harmful effects are seen as a result of mutation.
48
greatest impact of our application of energy transformations
coal burning, and other fossil fuel burning, chichis a huge factor in climate change
49
technology in reduction of the harmful impacts of energy transformations on earth
methane cracking (produces hydrogen fuel cells while releasing low amounts of carbon dioxide emissions). new ways of cement are being considered too red amount of carbon dioxide emissions produced. technology has been developed to produce electrical energy through nuclear fusion.
50
is it possible to reduce harmful effects of energy transformation by learning from our past mistakes?
yup. we analyze our mistakes with energy transformations to make sure that we do things differently in the future. we have learned from various nuclear power plant accidents, by implementing new safety inspections and safer technologies so that these accidents don't occur again.
51
what's "not useful" energy
some of the energy that is produced in an energy transformation. it is considered to be "lost"
52
in an exothermic reaction, reactants have ___ chemical potential energy than the products
higher
53
in an endothermic reaction, reactants have ___ chemical potential energy than the products
lower
54
isotopes
two or more forms of the same element with the same number of protons, but different number of neutrons. by having different numbers of neutrons, isotopes have different mass numbers. written using standard notation
55
radioisotopes
isotopes that have too many neutrons compared to protons, have too much energy, and are therefore unstable. they get rid of the extra energy by emitting particles from their nuclei, which are often accompanied by radiation
56
nuclear decay
to change an atom due to the emission of particles or radiation
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standard notation
chemical symbol + atomic number + mass number
58
radioactive decay
radioactivity sometimes results in the formation of completely new atoms. it results from having an unstable nucleus. when these nuclei lose their energy and break apart, decay occurs. radioactive decay releases energy from the nucleus as radiation. radioactive atoms release energy until they become stable, often as different atoms.
59
who identified 3 types of radiation using an electric field
rutherford
60
radiation
mechanism of energy transfer in which atoms or molecules give off energy in the form of electromagnetic waves
61
chemical reaction
process in which atoms of one or more substances are rearranged to form different substances
62
ionic compound and its Bohr diagram
consists of positively charged ions (cations), and negatively charged ions (anions). ionic bond is strong attraction that forms between oppositely charged ions. Bohr diagrams consist of protons and neutrons in centre, and all electrons. there are brackets and positive/negative signs around the final products
63
covalent compound and its Bohr diagram
compound that results when atoms of two or more elements bond covalently. covalent bond is strong attraction between atoms that form when valence electrons are shared. show all valence shells and electrons, and the molecules connected to each other. .
64
molecule
particle made up of 2 or more atoms bonded by covalent bonds
65
energy involvement in making/breaking of chemical bonds
energy is added until atoms/ions are no longer held together. amount of energy needed depends on the atoms or ions involved. when chemical bonds form, energy is released. when chemical bonds form and atoms achieve full valence electron shells, the atoms gain stability. thus, atoms go from low stability (high energy state) to greater stability (lower energy state), and "extra" energy is released.
66
law of conservation of mass
in a chemical reaction, total mass of substances used is equal to total mass of substances produced
67
chemical equation
representation of chemical reaction using words or chemical formulas
68
how to write skeleton and balanced chemical equations
skeleton - uses chemical formulas for reactants and products, but law of conservation of mass is not necessarily reflected. correct proportions of reactants and products may not be shown. balanced - same number of atoms of each element must appear on both sides of the arrow. achieved using coefficients.
69
difference between coefficient and subscript
coefficient - number placed in front of chemical formula in balanced chemical equation to show ratio of substances in a reaction. subscript - indicates number of atoms in a single molecule or formula unit
70
difference between chemical change and physical change
chemical change - change of matter that produces new substances (formation of bubbles). physical - change of matter that doesn't alter chemical identity or composition (freezing of water).
71
difference between exothermic and endothermic reactions, energy diagrams for both
exothermic - chemical reaction in which there is net release of energy to the surroundings. energy diagrams show products lower than reactants. endothermic - chemical reaction in which there is net absorption of energy from surroundings. energy diagrams show products higher than reactants.
72
synthesis reaction
chemical reaction in which 2 or more reactants combine to produce a single product. most are exothermic. A + B yields AB
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decomposition reaction
chemical reaction in which a compound is broken down into elements or simpler compounds.most are endothermic. AB yields A + B
74
difference between single and double replacement reaction
single replacement - chemical reaction in which an element and a compound react to produce another element and another compound. metal replaces metal: A + BX yields AX + B. non-metal replaces non-metal: AX + Y yields AY + X. double replacement - chemical reaction in which solutions of 2 ionic compounds react to produce 2 new compounds. AX + BY yields AY + BX
75
combustion
chemical reaction in which element reacts with oxygen to produce an oxide of the element and heat; also refers to burning of hydrocarbons to produce CO2 and H2O. for instance, sulfur will react with oxygen to produce sulfur dioxide... or CxHy + O2 yields CO2 + H2O
76
neutralization reaction
chemical reaction in which acid reacts with base to form a salt and water. HA (acid) + BOH (base) yields BA (salt) + HOH (water)
77
pH scale
numbered scale between 0 and 14 that indicates the acidity or basicity of a solution. acidic solutions = pH lower than 7. basic solutions = pH higher than 7. neutral solutions = pH of 7.
78
factors that affect reaction rates
surface area of solid reactant, concentration or pressure of a reactant, temperature
79
diatomic and polyatomic elements
di: hydrogen, nitrogen, oxygen, chlorine, bromine, iodine, fluorine. po: sulfur and phosphorus. BrINClHOFSP
80
Acids: also what are binary and Oxyacids
Acid: substance that releases hydrogen ions when dissolved in water. Binary acid: composed of hydrogen and non-metal, such as HCl (aq). Oxyacids: composed of hydrogen, oxygen, and another element (H2CO3 (aq)).
81
Base
Compounds that forms hydroxide ions when dissolved in water
82
Acid-base indicator
Chemical that changes colour in response to concentration of hydrogen ions in a solution
