Chemistry Overview Flashcards
What is: an Atom
An atom is the smallest “unit” of matter that forms a chemical element. Everything is composed of neutral or ionized atoms.
What is: the number on the top left of an atom’s symbol
Atomic number
What does the Atomic number tell us
It tells us the position on the periodic table, the number of protons it has and it DEFINES the ELEMENT
What is: the number on the bottom left of an atom’s symbol
Atomic MASS number
What does the Atomic MASS number tell us
It tells us the number of protons & neutrons together
All elements have equal amounts of ________ and ________ so that they are NEUTRAL in CHARGE
Electrons & Protons. (All elements have equal amounts of electrons and protons so that they are NEUTRAL in CHARGE)
What charge does a proton have?
Positive charge
What charge does an electron have?
Negative charge
What charge does an Neutron have?
Neutral charge
What is the amount of Electrons allowed in each shell of an atom
2,8,8
Where in an atom do the electrons go
The electrons are on the shells of atoms
Where in an atom do the protons go
The protons go in the middle/center of an atom
Where in an atom do the neutrons go
The neutrons go in the middle/center of an atom
What is an electron arrangement
The number of electrons in each shell
What is the electron arrangement of Sodium (Na) HINT: It has 11 protons & hence 11 electrons and it has 23 protons and neutrons together therefore there are 12 neutrons
2,8,1
What is a ‘group’ on the periodic table
A vertical column
What is a ‘period’ on the periodic table
A horizontal column
How many shells will an element in ‘Period’ 3 have?
If it is in ‘Period’ 3 it will have 3 shells
How many electrons will be in the outer shell if an element is in ‘Group’ 2
If it is in ‘Group’ 2 it will have 2 electrons in the outer shell
What is: An ion
An ion is an atom or group of atoms with a charge (+ or -)
How does an atom become an ion?
An atom becomes an ion by GAINING or LOSING ELECTRONS in order to have a FULL OUTER/VALENCE SHELL in order to be STABLE.
Q1. What does the Lithium atom have to do to become an ion? Lithium has the electron arrangement of 2,1 and has 4 neutrons, 3 electrons and 3 protons.
Q2. What would the Lithium atom’s charge be if it lost 1 electron (negative charge) in order to become an ion?
A1. Since Lithium only has 1 electron in its outer shell it would be easier to lose 1 electron than gain 7 to have a full outer shell and therefore become stable.
A2. Since an electron has a negative charge and there are always the same amount of electrons and protons (- & +) in an atom there would now be 1 extra proton (+) than electron (-) so therefore it would have a positive charge of 1. And would look like this: Li⁺
What does Beryllium atom have to do to become an ion? Electron arrangement of 2,2
Beryllium would find it easier to lose 2 electrons (-) than gain 6 so therefore there would be 2 more protons (+) than electrons (-) so therefore the Beryllium ion would have a positive charge of 2 and would look like this: Be⁺⁺
What is the chemical formula for Aluminium Chloride
Al³⁺ + Cl¯ → AlCl₃
Cl¯
Cl¯
What is an ionic compound?
Formed from combining a POSITIVE and NEGATIVE ion. MUST be NEUTRAL in charge.
In a chemical reaction what always occurs:
REACTANTS → PRODUCTS
What are the three acids and what are their formulas
- hydrochloric acid= HCl
- sulfuric acid= H₂SO₄
- nitric acid= HNO₃
What is the only base and what is its formula
Any chemical with the HYDROXIDE ION is a BASE
- sodium hydroxide= NaOH
Any chemical with the HYDROXIDE ION is a BASE
How is a SALT formed
A SALT is formed from the metal ion of the BASE (sodium ion) plus an ion from an acid)
What does HYDROCHLORIC acid form
HYDROCHLORIC acid forms CHLORIDES
What acid forms CHLORIDES
HYDROCHLORIC acid
What does SULFURIC acid form
SULFURIC acid forms SULFATES
What acid forms SULFATES
SULFURIC acid
What does NITRIC acid form
NITRIC acid forms NITRATES
What acid forms NITRATES
NITRIC acid
What is the formula for the Carbonate ion
CO₃²¯
What is the formula for the Bicarbonate ion
HCO₃¯
How do elements become ions? Why?
An atom becomes an ion by GAINING or LOSING Electrons in order to have a full outer/valence shell in order to be stable.
Explain how oxygen becomes an ion?
Oxygen gains 2 electrons to become an ion. 8 electrons (negative), 8 protons (positive), electron arrangement 2,6. 10e (-), 8p (+) → O²¯: Oxide ion. Full valence/outer shell=STABLE, electron arrangement: 2,8
Give the formula for aluminium chloride and aluminium oxide, explain the number in each.
1) AlCl₃= Al³⁺ lost 3e (-), 10e (-) 13p (+)= 2,8=STABLE.
2) Cl¯ gained 1e (-). 17p (+) 18e (-)= 2,8,8=STABLE.
In Aluminium Chloride the 3 electrons lost from aluminium go to each chlorine atom to become a chloride ion (Cl¯). The compound is NEUTRAL in charge (the positive and negative ion combine because they are attracted to each other).
In a practical investigation what is the Aim (the given)
The aim is how TEMPERATURE/SURFACE AREA/CONCENTRATION effects the RATE of REACTION (how quick)
What is the INDEPENDENT VARIABLE? (It is something “you” decide to change) And what do you need to do with it?
TEMPERATURE/SURFACE AREA/CONCENTRATION. You need to decide what the independent variable is and how you will measure it. You must choose at least 4 variables within your Independent variable. Such as TEMPERATURE: 20°C, 30°C, 45°C & 70°C measured with a thermometer.
What is the DEPENDENT VARIABLE
What you measure as a result. How (from… until…) and with what…
What are CONTROL VARIABLES
What you keep the same. (Give values and how they are measured). REPEAT at least three times e.g trial 1, trial 2, trial 3.
What are the steps involved in a method for a practical investigation
- What you changed and how
- What are you measuring and how
- What are you keeping the same and how
- Repeats
- Any other relevant
How do you show your results
In a table label somewhere with time (s) and whatever the other variable is. Have it set out with the variables on the side and trial 1, 2, 3 and the average along the top. Draw a line graph.
How do you layout your line graph for a practical investigation
Time (s) is always on the vertical axis, then have the lowest of the variables on the left going up to the biggest. Only plot the averages. Start measuring from the very first line don’t start in a random place. Start from 0,0. Always have equal gaps between everything. Label the sides with the variable.
What is the CONCLUSION for a practical chemistry investigation
As TEMPERATURE/SURFACE AREA/CONCENTRATION INCREASES/DECREASES the TIME INCREASES/DECREASES hence the RATE of REACTION INCREASES/DECREASES. I know this because my average times for ____ was……, ____ was….., ____ was…. etc.
EXAMPLE:
As temperature increases the time decreases hence the rate of reaction increases. I know this because my average times for ____ was…, ____ was….., ____ was…. etc.
What are the steps involved in writing ACCURACY
- What were the control variable and what were they measured with…. why…..
e. g 2cm Mg strip measured with ruler because there was the SAME NUMBER OF PARTICLES in each trial. - 4mL of HCl measured with a measuring cylinder because there needs to be the same number of HCl PARTICLES in each trial. Draw measuring cylinder with a meniscus and arrow pointing out measured at eye level to avoid PARALLEX error and at the bottom of the MENISCUS (the curved part).
- The temperature was…. measured with a thermometer. This needs to be the same in order to have the same speed therefore the same kinetic energy.
- Concentration
- Surface area
Why do you measure liquids from the bottom of the meniscus?
To avoid PARALLEX error
What is the meniscus?
The curved part that you see if you look at a liquid at eye level.
How do you write up RELIABILITY in a chemistry practical investigation
- I measured the time with a stopwatch because it is a better instrument (more accurate and sensitive) than a clock.
- I used 5mL and 10mL measuring cylinders. They are more accurate and reliable compared to a beaker of larger measuring cylinder.
- I repeated each trial 3 times to eliminate any outliers and any other errors.
How do you write up DISCUSSION in a chemistry practical investigation
Surface Area:
When the surface area INCREASES there are MORE PARTICLES EXPOSED therefore MORE COLLISIONS per second/ in the same period of time therefore GREATER RATE of REACTION.
Concentration:
When the CONCENTRATION is HIGHER there are MORE PARTICLES in the same SPACE therefore MORE SUCCESSFUL COLLISIONS per second therefore a GREATER RATE OF REACTION.
Temperature:
What is RATE OF REACTION
The rate is “how quickly” chemicals react. In order for 2 chemicals to react they have to COLLIDE with enough energy and correct orientation. PARTICLES will be used to describe any element or compound (e.g Mg or HCl). The rate of reaction is the NUMBER OF REACTION per second/or per unit of time. The factors effecting the rate of reaction are: SURFACE AREA, TEMPERATURE, CONCENTRATION.
How do you understand rate of reaction for SURFACE AREA
If you have a box that box has: both same mass and particles. If you cut that exact same box in half it would have: larger surface area therefore more PARTICLES can collide per second therefore greater RATE of REACTION.
How do you understand rate of reaction for TEMPERATURE
Increasing the TEMPERATURE increases the KINETIC ENERGY of particles hence the SPEED which will cause more COLLISIONS in the SAME time hence a GREATER RATE OF REACTION.
EXAMPLE: (If you have a solution and you imagine all of the little dots of the particles in that solution. At their normal temp. they will have short arrows pointing off in different directions. If you heated it up those arrows would lengthen showing the dots speeding up. Higher speed, higher temperature.)
How do you understand rate of reaction for CONCENTRATION
A higher concentration means that there are more PARTICLES in the SAME SPACE therefore there will be more COLLLISIONS in the SAME time therefore greater RATE of REACTION.
EXAMPLE:
(Imagine a beaker in that beaker are gray dots they are representing H₂O particles there are way more gray dots than red dots representing HCl particles. A greater concentration of HCl creates more red dots than gray dots. Higher or lower concentrations alter the ratio between the ‘dots’).
Explain how Mg becomes an ion
Mg: 12 protons (+), 12 electrons (-). It is easier for Magnesium to lose 2 electrons to gain a full valence shell and become stable. It’s electron arrangement is 2,8,2 draw Mg atom. After losing two electrons it becomes a Magnesium ion, Mg²⁺. 10e (-), 12p (+)= Mg²⁺
Give the formula for Magnesium Chloride
Mg²⁺ +Cl¯ → MgCl₂
Give the formula for Calcium Nitrate
Ca²⁺ + NO₃¯ → Ca(NO₃)₂
NO₃¯
Give the formula for Iron (Ⅲ) Oxide
Fe³⁺ + O²¯ → Fe₂O₃
Fe³⁺ O²¯
O²¯
Explain the formula for Iron (Ⅲ) Oxide
- Opposite charges attract
- Neutral in charge
- Each Fe(Ⅲ)³⁺ has lost 3e¯
- Each O²¯ has gained 2e¯
- There has been a total of 6e¯ exchanged
- There are 2 Fe(Ⅲ)³⁺ for 3 O²¯ ions.
What would the PRODUCTS be if the REACTANTS are: Magnesium hydroxide + hydrochloric acid
Magnesium Hydroxide + hydrochloric acid → Magnesium Chloride + Water
What would the PRODUCTS be if the REACTANTS are: Calcium Carbonate + Nitric Acid →
Calcium Carbonate + Nitric Acid → Calcium Nitrate + Water + Carbon Dioxide
What would your observations be if the experiment was redone at a higher temperature. After watching a chemistry practical where a reactive stone is placed in a solution and fizzes.
Observations: Bubbles/Fizzing • More bubbles in the same time • More Kinetic energy, so more speed • More collisions in the same time • Greater rate of reactions.
What are the 2 most important words to remember for Chemistry
- RATE of REACTION
* PARTICLES
What does an Acid produce in water?
H⁺ ions.
What does an Base produce in water?
OH¯ ions
When answering a question on how to identify a neutral compound using litmus paper. What do you need to add to saying that you would need to add blue litmus paper and red litmus paper to the solution and if both did not change colour then it would be a neutral solution. To make it an excellence answer?
You need to add that if blue litmus paper did turn red, then that would mean that, that compound is acidic and that if red litmus paper did turn blue, that would mean that, that compound is a base.
How do you make salt in a lab?
You need to add a acid and a base together until they react and the solution is neutral (you check this by using litmus paper and universal indicator). You then need to put the contents into an evaporating dish so that the water can evaporate into the neutral salt. You then need to leave it for a few days to ensure that all of the water has evaporated as this process takes time or you could heat it up using a bunsen burner if you wanted to speed up the process.
What is your answer to: Why does a rate of reaction go flat as a reaction progresses on a graph?
As reactant particles react and are converted into products, the concentration of reactants decreases, so therefore the rate of reaction decreases until it gets to zero and the graph goes flat.
What is a catalyst?
A Catalyst is any substance that increases the rate of a reaction without being consumed itself.
What is ionic bonding?
ionic bonding is where atoms with too many valence electrons donate those electrons to atoms with not enough valence electrons. This transfer of electrons causes ions to form and the electrostatic attraction between the oppositely charged ions is called an ionic bond. For example, Na needs to lose one electron to have a full valence shell, and Cl needs to gain an electron to gain a full valence electron shell, so therefore Na will donate an electron to Cl,
resulting in Na⁺ and Cl¯ forming, which results in an ionic bond called NaCl.
What do atoms in the same group in the periodic table have in common?
Atoms that are in the same group in the periodic table will have the same number of valence electrons and therefore have the same charge.
On a chemistry graph of the volume of gas produced there are two lines number 1 has a steeper slope number 2 has a less steep slope they both eventually level off at the same place. Which one produces more gas in total.
Neither. They both produce the same amount of gas. However number 1 produces it quicker therefore it has a higher concentration.
On a chemistry graph of the volume of gas produced there are two lines number 1 has a steeper slope number 2 has a less steep slope they both eventually level off at the same place. Which one has a higher concentration. Explain your answer.
Number 1 has a higher concentration because it produces the same amount of gas in a shorter time than number 2. This is because it has a higher concentration therefore more particles in the same space therefore more collisions tin the same time therefore greater rate of reaction. Number 1 has a greater gradient, so therefore more gas produced in the same time.
What do sodium bicarbonate + sulfuric acid produce?
sodium bicarbonate + sulfuric acid → sodium sulfate + water + carbon dioxide
What is an Acid?
An ACID is a chemical that will “release” the H⁺ ion in water (it will DISSOCIATE)
What are the 3 acids and their symbols?
- Hydrochloric acid=HCl
2 Sulfuric acid= H₂SO₄ - Nitric acid=HNO₃
What is a Base?
A BASE is a chemical that will “release” the OH¯ ion in water and form an ALKALI solution.
What is the pH scale?
The pH scale is a measure of how acidic a solution is. It measures the presence of H⁺ ions compared to OH¯ ions. When universal indicator is added the solution goes coloured based on pH.
What numbers on the pH scale are strong Acids and what are their colours?
Strong Acids are 0-2 on a pH scale and have a colour of Red.
What numbers on the pH scale are weak Acids and what are their colours?
Weak Acids are 3-6 on a pH scale and have a colour of orange to yellow.
What number on the pH scale is neutral and what is its colour?
Neutral is number 7 and has the colour green.
What numbers on the pH scale are weak Bases and what are their colours?
Weak Bases are numbers 8-11 are the colour blue.
What numbers on the pH scale are strong Bases and what are their colours?
Strong Bases are numbers 12-14 and are the colour purple.
What is a: Quantity
A quantity is something you can measure.
What is the quantity: time’s quantity symbol?
t
What is the UNIT for the quantity: Time and what is it’s UNIT symbol
Seconds. UNIT symbol=s
What is the Quantity: Force’s Quantity symbol
F
What is the UNIT for the Quantity Force and what is it’s UNIT symbol
Newton symbol= N
What is the Quantity: Speed’s quantity symbol
v
What is the UNIT for the quantity speed and what is it’s UNIT symbol
Metres per second. Symbol= m/s
What is the UNIT for the quantity Temperature and what is it’s UNIT symbol
Degrees celsius. Symbol= °C
What is the Quantity distance’s quantity symbol
d
What is the UNIT for the quantity distance and what is it’s UNIT symbol
Metres. Symbol= m
What is the Quantity Power’s quantity symbol
P
What is the UNIT for the quantity power and what is it’s UNIT symbol
Watts. Symbol= W
What is the Quantity Area’s quantity symbol
A
What is the UNIT for the quantity Area and what is it’s UNIT symbol
Metres squared. Symbol= m2
What is the Quantity Energy’s quantity symbol
E
What is the UNIT for the quantity energy and what is it’s UNIT symbol
Joules. Symbol= J
What is the Quantity volume’s quantity symbol
V
What is the UNIT for the quantity volume and what is it’s UNIT symbol
Millitres. Symbol = mL
What is the UNIT symbol for the quantity concentration
molL¯¹
What is an Anion
Anions have more electrons than protons and so have an overall negative charge
What is a Cation
Cations have less electrons than protons and so have an overall positive charge.
What charge are attracted to each other
Opposite charges attract
What is another word for a BASE
Basic
What happens to Blue Litmus paper if the chemical is an ACID
Blue litmus paper turns red if the chemical is an acid
What happens to Blue Litmus paper if the chemical is neutral
It will stay blue
What happens to Red Litmus paper if the chemical is neutral
It will stay red
What happens to Red Litmus paper if the chemical is a BASE
It will turn Blue
What do you need to do if your red/blue litmus paper stays the same colour
You need to test with the opposite colour if both types of Litmus paper stay their original colour the chemical is neutral
If the solution has a pH of 0-2 what will the colour be and what type of acid will it be?
If the solution has a pH of 0-2 the colour will be red (with universal indicator) and it will be a strong ACID
If the solution has a pH of 0-2 is red and is a strong ACID will there be more H⁺ ions or OH¯ ions?
If it is a strong ACID there will be more H⁺ ions than OH¯ ions. (H⁺)»_space; (OH¯). Concentration of H⁺ ions is much, much higher compared to OH¯ ions.
If the pH of the solution increases to 3-4 what is the colour and then increases slightly again to 5-6 what is the colour and what type of ACID are they?
As the pH increases to 3-4 the colour will be orange and then when it increases to 5-6 the colour will be yellow. They are WEAK ACIDS.
If the pH of a solution increases to 3-4 and 5-6 and have the colours of orange to yellow and are WEAK ACIDS will there be more H⁺ ions or OH¯ ions?
If it is a WEAK ACID there will be more H⁺ ions than OH¯ ions. (H⁺) > (OH¯). Concentration of H⁺ ions is greater than OH¯ ions.
If the pH of a solution is 7 what colour is it and what is it?
If the pH of a solution is 7 the colour will be green and it will be NEUTRAL.
If the pH of a solution is 7 and the colour is green and it is NEUTRAL will there be more H⁺ ions or OH¯ ions?
If the pH of a solution is 7 the colour is green and the solution will be NEUTRAL therefore there will be an equal amount of H⁺ ions to OH¯ ions. (H⁺) = (OH¯). The concentration of H⁺ ions and OH¯ ions is EQUAL.
If the pH of a solution is 8-11 what colour is it and what type of BASE is it?
If the pH of a solution is 8-11 the colour is blue and it is a WEAK BASE.
If the pH of a solution is 8-11 the colour is blue and it is a WEAK BASE are there more H⁺ ions or OH¯ ions?
If the pH of a solution is 8-11 the colour is blue and the solution is a WEAK BASE it will have more OH¯ ions than H⁺ ions. (H⁺) < (OH¯). The concentration of OH¯ ions is greater than H⁺ ions.
If the pH of a solution is 12-14 what colour is it and what type of BASE is it?
If the pH of a solution is 12-14 the colour is purple and it is a STRONG BASE.
If the pH of a solution is 12-14 its colour is purple and it is a STRONG BASE are there more H⁺ ions or OH¯ ions?
If the pH of a solution is 12-14 the colour is purple and it is a STRONG BASE there will be more OH¯ ions than H⁺ ions. (H⁺) «_space;(OH¯).
How do you explain why a rate of reaction graph goes flat
As reactant particles react and are converted into products, the concentration of reactants decreases and therefore the rate of reactions decreases until it becomes zero and the graph
becomes flat.
What do catalysts do?
Catalysts lower the activation energy (energy needed) and so, therefore, more of the collisions are successful as the required energy for a successful collision is less.
What are the Polyatomic ions?
The Polyatomic ions are: • NH₄⁺ (Ammonium ion) • OH⁻ (Hydroxide ion) • NO₃⁻ (Nitrate ion) • HCO₃⁻ (Hydrogen Carbonate/Bicarbonate ion) • SO₄²⁻ (Sulfate ion) • CO₃²⁻ (Carbonate ion)
Is: Sodium hydrogen carbonate (NaHCO₃) a BASE or an ACID?
Sodium hydrogen carbonate (NaHCO₃) is a BASE.
Is: Ammonia (NH₃) a BASE or an ACID?
Ammonia (NH₃) is a BASE.
What do you have to do with a Polyatomic ion?
If you use a Polyatomic ion more than once you must put brackets around it. Example: Cu(NH₄)₃
