C4 Flashcards
How can you test for hydrogen?
Hydrogen will make a squeaky pop sound when exposed to a lit splint
What is the reaction between a group 1 element and oxygen?
Metal + oxygen -> metal oxide
State ad colour of bromine at room temp
Red-brown liquid
Physical state of group 0 elements
Gases
How can you test for oxygen?
Oxygen will relight a glowing splint
When performing the sodium hydroxide tests for metal ions, what is the colour of iron 2+ precipitate?
Green
What colour will sodium ions burn with ?
Yellow flame
Why are noble gases inert?
They already have a full outer-shell of electrons, so don’t need to gain or lose any electrons
Why should the wire be clean for a flame test?
So there are no impurities which could alter the colour of the flame
What colour will calcium ions burn with?
Orange-red flame
What colour will potassium ions burn with?
Lilac
When performing the sodium hydroxide test for metal ions, what is the colour of the copper precipitate?
Blue
Why do halogens become less reactive as you move down group 7 of the periodic table?
As you go down the group, atomic radius and shielding increase (which outweighs the increased nuclear charge).
This means there is a weaker electrostatic attraction between the nucleus and the electron it is trying to gain.
This means more energy is required for a reaction to occur.
When testing for halides, what colour precipitate does bromide form?
Bromide ions form a cream precipitate.
Why do alkali metals become more reactive down the group?
As you go down the group, atomic radius and shielding increase (which outweighs the increased nuclear charge).
This means there is a weaker electrostatic attraction between the outer-most electrons and the nucleus.
The means that the amount of energy required to lose the outer-most electron decreases, which makes it easier for a reaction to occur.
State the 3 trends seen in group 1 metals as you go down the periodic table.
Increased reactivity.
Lower melting and boiling points.
Higher atomic mass
What colour will copper ions burn with?
Copper ions burn with a green flame.
What are the properties of group 1 metals?
Soft.
Low density.
Very reactive.
Weak.
Relatively low melting points (compared to other metals).
What colour will lithium ions burn with?
Lithium burns with a crimson flame.
What is the state and colour of fluorine at room temperature?
Fluorine is a yellow gas at room temperature.
State the three trends in the group 7 elements as you go down the periodic table.
Decreased reactivity.
Higher melting/boiling points.
Higher atomic mass.
How do you test for sulfate ions?
React the substance with dilute hydrochloric acid (HCl) to remove any carbonate ions.
Add barium chloride solution.
If sulfate ions are present, it will form a white precipitate of barium sulfate.
What is an anion
a negatively charged ion.
How do you test for metals using sodium hydroxide?
Add sodium hydroxide to the mystery compound.
The colour change will indicate which metal is in the compound.
When testing for halides, what colour precipitate does chloride form?
White
When performing the sodium hydroxide test for metal ions, what is the colour of the Fe3+ (iron 3+) precipitate?
Brown
How can you investigate the reactivity of metals using temperature change?
React each of the metals with either water or acid over a set period of time.
Ensure that the surface area and the mass of the metal is the same each time.
Measure the rise in temperature.
The greater the temperature change, the more reactive the metal must be.
When testing for halides, what colour precipitate does iodide form?
Iodide ions form a yellow precipitate.
What is the reaction between a group 1 element and water?
Metal + Water ➔ Metal Hydroxide + Hydrogen
Name the first 4 group 7 elements, starting at the top of the group
1Fluorine
2Chlorine
3Bromine
4Iodine
State and explain the trend in the boiling points of noble gases as you move down group 0 of the periodic table.
The boiling points increase as you move down the group. This is because the atoms have more electrons, and so can form more intermolecular forces, which will require more energy to overcome.
How can you test for carbon dioxide?
When bubbled through limewater, carbon dioxide will turn the limewater cloudy.
What type of bonds do halogens form with metals?
Halogens form ionic bonds with metals
How do you test for carbonate ions?
React the substance with dilute hydrochloric acid (HCl).
If the substance contains carbonate ions, it will produce carbon dioxide gas which will bubble out of the solution.
Collect the gas and bubble it through limewater.
If the limewater turns cloudy, it confirms the gas is carbon dioxide.
Confirmation that the gas is carbon dioxide is confirmation that the original substance contained carbonate ions.
What is a cation?
A cation is a positively charged ion.
How can you test for chlorine gas?
It turns damp red litmus paper from red to white.
What is the state and colour of iodine at room temperature?
Iodine is a dark grey solid, which gives off purple fumes.
When performing the sodium hydroxide test for metal ions, what is the colour of the magnesium precipitate?
White
Outline the steps required to perform a flame test.
Take a platinum (or nichrome) wire loop, and clean it by dipping it in some dilute hydrochloric acid, rinsing it in distilled water, and then heating it over a Bunsen burner flame.
Dip the wire loop into the compound you want to test.
Hold the wire loop in the clear blue part of the Bunsen burner flame (this is the hottest part).
See what colour the flame turns as the compound burns.
In displacement reactions, which ions are reduced?
Metal ions are reduced - this means they gain electrons.
How do you test for halide ions?
React the solution with nitric acid to remove any carbonate ions or sulfate ions.
Add silver nitrate solution.
If a white precipitate forms, the substance contains chloride ions.
If a cream precipitate forms, the substance contains bromide ions.
If a yellow precipitate forms, the substance contains iodide ions.
When performing the sodium hydroxide test for metal ions, what is the colour of the calcium precipitate?
White
When performing the sodium hydroxide test for metal ions, what is the colour of the aluminium precipitate?
White at first.
Then redissolves in excess sodium hydroxide to form a colourless solution
What is the effect of using reactants with increased reactivity in a reaction?
Increased reactivity means the reaction will take place more quickly, or more vigorously.
Would powered metal, or a single chunk (both the same mass) react more vigorously?
Powered metal, as it would have a larger total surface area.
What state and colour is chlorine at room temperature?
Green gas
