GRADE 9 SCIENCE EXAM Flashcards
what is the charge, weight and where are they located? protons, neutrons, electrons
who discovered them
PROTONS -positive -Located inside the nucleus - 1amu - Henry Mosely, proved they are in the nucleus NEUTRONS -no charge -located inside the nucleus -1amu - Chadwick discovered them ELECTRONS -negative -located around the nucleus -0amu - J.J Thompson
what is matter
- anything that has mass and weighs something
- takes up volume
- mass is constant
- mass and weight are not the same thing
who is Empedocles
- philosopher
- proposed that matter was made of 4 elements
1. air 2. earth 3. fire 4. water - he thought if you mixed these elements together in different amounts, you would make different substances
who is Democritus
- suggested that matter was made of tiny particles, which couldn’t be broken down any further
- called these particles atoms: from the Greek word atmos meaning indivisible
- thought different types of matter were made of different types of atoms
- at the time, Democritus’ idea was not accepted because Aristotle did not think it was true.
who is Aristotle
- came up with the theory called transmutation- one form of matter could be turned into another.
- you could turn something worthless into lead, into something valuable like gold. this paved the way for alchemists
what are alchemists
-first people to perform experiments
they had three main goals:
-change bas metals into gold
-find a substance for eternal life
-produce a universal solvent (will dissolve anything)
- none of these goals were reached, however they are important to history because:
-they discovered many elements and their property, including chemical symbols
- they invented many lab tools we still use today
- they actually performed these experiments
define ductility
-ability to be shaped or stretched into a wire without breaking
define malleability
ability to be hammered pressed or rolled into thin plates
define conductivity
how easily heat and electricity can pass through a substance
define lustre
how shiny a material is
metals
- make up about 75% of the P.T
- located all over the P.T, but are concentrated on the left side
- are shiny, conduct heat, can make wires or be stretched into sheets
non-metals
- make up about 15% of the P.T
- found on the far right side of the P.T
- are poor conductors, not shiny, are brittle and not ductile
define metalloids
- make up about 6% of the elements
- located on the “staircase” of the P.T
- have properties of both metals and non-metals
atomic mass
- atomic weight rounded to the nearest whole number
- average mass of an element
- total number of protons and neutrons in the nucleus
atomic number
- tells us how many protons and electrons are in the nucleus
-the P.T the atomic number is the number that identifies the element
elements are arranged from left to right, top to bottom in order of their atomic number
how to find the # of neutrons in an atom
- subtract the number of protons (atomic number) from the atomic mass
who is Mendeleev
- known as the father of the P.T
- arranged the 63 known elements in order of their atomic mass and saw the repeating patterns of properties
- Mendeleev left spaces for undiscovered elements, correctly predicted where new elements would be found
- his table summarized the structure and property of the elements
- the problem with his table, occurs when atoms are arranged by mass only properties did not always match up when atomic mass was used.
- by matching properties, he was able to place iodine and tellurium in their proper places.
what is a period
- vertical rows with numbering 1-7 from top to bottom
what is a family/group
- horizontal columns labeled 1-18.
- there are 6 families
- in each column the elements have similar chemical properties
family/- hydrogen
- family of its own
- has one valence electron
- reacts vigorously
- cannot exist at a single atom (too reactive) but as a molecule H2.
family-alkali metals
- reacts vigorously with many other substances
- larger the alkali metal, the more reactive
- located at group 1
family-alkali earth metals
- reacts fairly vigorously
- the larger the metal, the more reactive
- located at group 2
family-chalcogens
- quite reactive, but not as much as halogens
* located at group 16
family-halogens
- react very vigorously with nearly everything
- the least reactive is still corrosive
- larger the atom, less reactive
- located at group 17
family-noble gases
- are unreactive (inert)
* located at group 18
what are Bohr diagrams
- each orbit can hold a specific amount of electrons
first shell= 2 electrons
second shell and third shell= 8 electrons - electrons on the outer shell are known as valence electrons
chemical reactivity
-when two or more elements mix, a chemical reaction takes place
-chemical reactivity depends on the number of valence electrons
-in order for an element to be considered stable/unreactive, it must have a full outer shell
-to get a full outer shell an atom can:
gain, lose, or share electrons
chemical reactivity-hydrogen
- has 1 valence electron
- can gain an electron to fill its outer shell
- it can also lose an electron to “fill” its outer shell
- is very, very reactive and explosive
chemical reactivity-alkali metals
- has 1 valence electron
- will lose the 1 electron, rather than gain 7 more to fill the outer shell
- are very reactive
chemical reactivity-alkaline earth metals
- have 2 valence electrons
- would rather lose 2 than gain 6 more
- less reactive than alkali metals
- still very reactive because its quite easy to lose 2 electrons, but not as easy as losing one
chemical reactivity-chalcogens
- have 6 valence electrons
- would rather gain 2 electrons that lose all 6
- are quite reactive, since it is fairly easy to find 2 electrons, not as reactive as haolgens
chemical reactivity-halogens
- have 7 valence electrons
- will gain 1 more electron to fill their outer shell(easier than losing 7)
- very reactive because, like alkali metals, they are very close to being like the noble gases so they react vigorously to gain an electron
chemical reactivity-noble gases
- have 8 valence electrons which means there outer shell is full
- this means they are unreactive
- does not want to mix or react with other elements
who is John Dalton
atomic model= the billiard ball
- said that atoms were tiny particles that could not be divided.
- atoms of the same elements are exactly alike
- atoms are nether destroyed or created
who is J.J Thompson
atomic model= the plum pudding model
- discovered electrons in 1897.
- studying the effects of electricity passing through a gas
- It proved that smaller particles inside the atom existed
who is Ernest Rutherford
atomic model=the planetary model
- the nucleus is a very tiny and positively charged core of an atom.
- looked like the sun (nucleus) and the planets orbiting around it (electrons)
who is Niels Bohr
atomic model=electron shell
- electrons orbit around the nucleus in paths (orbits or shells that are circular)
- each orbit was a certain distance from the nucleus and could only hold a certain number of electrons
what is qualitative data
-physical property of a characteristic of a substance that can be described but not measured
what is quantitative data
- Quantitative physical property is a characteristic of a substance that can be measured numerically
- density is very useful in quantitative physical properties
density
- how tightly packed atoms are in a space or substance
the formula for finding density- mass-volume=density
or the pyramid=mass on top and density on the bottom left with volume on the right (cover which ever you are trying to divide
solutions
- in a solution, the different substances that make it up are not separately visible
- one substance is dissolved in another
- sometimes called homogenous mixtures
mechanical mixture
-different substances that make up the mixture are visible
-sometimes its easy to see the different parts of the mixture and other times it is not
sometimes called heterogeneous mixtures
a mixture
- combination of pure substances
- they stay in there pure form when a compound is formed
homogenous solutions
-pure substances and to mixtures that are of uniform composition-they appear to be a pure substance
heterogenous solutions
mixtures that are not uniform in composition
-not the same, you can see different parts
chemical change
-is a change that results in a new substance(s) being formed
-important word is NEW
- chemical change involves the making or breaking of bonds between atoms
-makes a new substance that wasn’t there before
SIGNS OF SHOWING CHEMICAL CHANGE:
-change colour
-gives gas or fizzes
-object melts of disappears
-heat
-new substance formed?
-can we get the original substance back?
physical change
-change in the state of matter
ex. ice melting-going from a solid to liquid
-actual molecule or the arrangement of the atoms have not changed-just the state of matter
-also can be change in just appearance
SIGNS OF PHSYSICAL CHNAGE:
-state
-hardness
-malleability
-ductility
-melting and boiling point
-viscosity
-solubility
-density
pure substance
- sample of matter with definite and constant composition
- truly 1 substance with nothing mixed in, composition or makeup does not change
compounds
- made by combining 2 or more elements
- molecules made up of different types of atoms
- can be broken down into simpler elements
- are formed when elements share or transfer electrons
elements
- simplest form any material can be broken down into
- impossible to break something down anymore (gold)
chemical formulas
-when two elements are mixed in a chemical reaction, we form a new substance or compound
-when a compound is formed, we have a new chemical formula
you can also have diatomic molecules(2 of the same atom)
or polyatomic molecules=more than 2 atoms
exothermic
-hotter than surroundings
endothermic
-cooler than surroundings
Define lysosomes
• helps recycle food waste
Define chloroplast
- green organelle
- in plant cell
- carry on photosynthesis
Define mitochondria
• makes energy for cell
Describe the cycle of organelles
Ribosomes bring simple pieces together to make protein.
Some ribosomes float around in cytoplasm, others attach to endoplasmic reticulum.
Then, proteins are passed along endoplasmic reticulum and passed to Golgi bodies.
Golgi body sorts them out, puts each kind into storage, called a vesicle.
Vesicles move around, deliver proteins, food, nutrients, and water into and out of cells as well as around cell.
Then vacuoles temporary store things, then pass waste to lysosomes.
They are recycled back to other organelles like ribosomes to make new proteins.
Which cell is photosynthesis used in?
Describe the process of photosynthesis
Plant cells
Light & energy-
Usually sunlight
Carbon dioxide-
Gas in air around plant
Water-
Water comes from roots
In mitochondria
Food-
Glucose is stored in vacuoles
Oxygen-
Waste product which plant gives off to air
Define Golgi body/ apparatus
- stores proteins Inside a membrane
* in an even smaller package called a vesicle
Define nucleus
- organelle that controls everything that happens
* stores DNA
What are the organelles found inside of a plant cell?
Label them on a diagram (paper)
What organelles are only found inside of a plant cell?
vacuole • cytoplasm • Golgi body/ apparatus • cell wall • nucleus • nuclear membrane • endoplasmic reticulum S.E.R//// R.E.R • cell membrane • mitochondria • vesicles • lysosomes • ribosomes • chloroplast
The two only found in plant cells are :
• chloroplast
• cell wall
What are the organelles found inside of an animal cell?
Label them on a diagram (paper)
vacuole • cytoplasm • Golgi body/ apparatus • nucleus • nuclear membrane • endoplasmic reticulum S.E.R//// R.E.R • cell membrane • mitochondria • vesicles • lysosomes • ribosomes
The jelly like substance found inside a cell is called?
Cytoplasm
Define eukaryotic cells
What kind of things are in these cells?
- cell with membrane
* nucleus, mitochondria, endoplasmic reticulum etc
Define prokaryotic cells
Give an example
- cell without membrane
* bacteria
Define proteins
complicated molecule
• made in cell by ribosomes
Define a vacuole
What are the different types?
Which cell are they located in?
• place to store food or wastes
Animal cell-
• Multiple vacuoles spread all over the place
• smaller
Plant cell-
• One central vacuole
• bigger
Define vesicles
• acts like postal delivery
Sends messages to places or makes something
Define the endoplasmic reticulum
What are the different types?
What is the difference?
• moves things around in cells tubes
Smooth endoplasmic reticulum-
Has no ribosomes attached to it
Rough endoplasmic reticulum-
Has ribosomes attaches to it
Define ribosomes
• makes proteins
Define photosynthesis
- process in plant cells
* produces food for energy
asexual reproduction
- do not need a partner to reproduce
- an exact replica offspring
sexual reproduction
- do need a partner to reproduce
- has some characteristics of the mom and dad
define genotype
- the scientific term for describing a gene or characteristic ex. Ff, FF, ff
- the dominant (FF or Ff) is always displayed
define phenotype
- something you can see or know about
ex. brown hair, blue eyes, freckles
define homozygous and give examples
-homozygous is when you have two of the same genes. ex. FF, or ff.
-you have two of the same genes for a given trait.
- there are recessive ff, and dominant FF
it is also called a pure-breed
ie. homozygous recissive ff
homozygous dominant FF
define heterozygous give examples
- heterozygous is when you have a mixed of dominant and recessive gene, or two different genes for a trait
- described as Ff
- also called a hybrid
what is DNA
- is the hereditary material in humans and almost all other organisms.
- it is stored as a code
define an element
- Elements are chemically the simplest substances and hence cannot be broken down using chemical reactions.
define an atom
- smallest unit of matter
- basic building block of chemistry and life
define chemical symbol
- they are abbreviations used on the periodic table when showing an element.
ex. Gold- Au
dominant gene
- the dominant gene is always displayed
- FF, or Ff- the dominant gene will take over
recessive gene
- it only happens when both genes are lowercase or recessive.
- ff, Ff
define insulator give example
- insulator is a object in which electrons can not move freely from atom to atom.
ex. oil, fur, silk, wool, rubber
define conductor give example
- conductor is a substance in which electrons can move freely from one atom to another.
ex. silver, copper, gold, aluminum
what is friction, what is charge?
what is the difference
- friction produces static electricity
- charge makes electrons become negatively or positively charged
- the difference is friction makes the electrons go away and charge makes them negative or positive
what is lightning? explain the steps of what happens before it strikes an object
- lightning is a spark that jumps from cloud to cloud from build up of static electricity
- lightning builds up enough force until it strikes
- it will usually strike a tall object
what is current
- depends on how many electrons pass a point in a circuit every second
- how fast electrons go through
- it is measured in Amps.
- I is current ad is measured in A (amperes)
what is resistance
- ohms measure the resistance to the flow of electrons
- it is measured in Ohms.
- tries to stop electrons from flowing through
- R is resistance and it is measured in R (Ohms)
what is power
-P is power and measured in P (watts)
how do you convert time?
- you must convert time into seconds when finding different things
- t is time and is measured in s (seconds)
what is charge
q is charge and is measured in C (coulombs)
what is energy
E is energy and is measured in J (joules)
the electrostatic series
- created to show how strong or weak a substance has on electrons.
- the weaker the hold of electrons, the higher up on the series it is
- the stronger the hold the lower down on the series
- the substance with the stronger hold will take electrons away and the weaker substance will become negatively charged
what is the law of attraction and repulsion
-Like charges repel each other; unlike charges attract. two negative charges repel one another, while a positive charge attracts a negative charge.
what is mitosis, why does it occur?
- mitosis makes body cells
- it is important for the growth and development of our bodies as well. Mitosis produces new cells, and replaces cells that are old, lost or damaged.
what is meiosis, why does it occur?
- meiosis makes sex cells
- its goal is to make daughter cells with exactly half as many chromosomes as the starting cell.
what are gametes
- gametes are an organisms reproductive cell
- it is half the genetic material necessary to form an organism
what are zygotes
- fertilized egg cell that results from the union of a female gamete with a male gamete (sperm).
- the zygote stage is brief and is followed by cleavage, when the single cell becomes subdivided into smaller cells.
what is an embryo
- embryo is the early stage of development of a multicellular organism.
haploid (1N)
- Haploid describes a cell that contains a single set of chromosomes.
- Gametes are haploid cells that contain 23 chromosomes each
diploid (2N)
- Diploid describes a cell that contain two copies of each chromosome
- diploid cell has 46 chromosomes
sex cells
- sex cells are the things that make the organism
- in the female it is the egg or ovum
- in the male it is the sperm
sperm
-sperm is the male reproductive cell
egg
-egg is the female reproductive cell
chromosomes
-A chromosome is a strand of DNA that is encoded with genes. In most cells, humans have 22 pairs of these chromosomes plus the two sex chromosomes (XX in females and XY in males) for a total of 46.
fertilization
-The process of combining the male gamete, or sperm, with the female gamete, or ovum. The product of fertilization is a cell called a zygote.
