Paper 1 (Questions) Flashcards
What is a control variable?
A variable that is kept the same
What is an independent variable?
A variable that you change
What is a dependent variable?
A variable that you are measuring
Predict the reactivity of beryllium compared with magnesium
Beryllium is less reactive because there is a greater attraction between nucleus and outer shells meaning that more energy is needed to remove electrons
What is the formula for nitric acid?
HNO3
Describe the method to investigate how the temperature changes when different masses of ammonium are dissolved in water
- Use a suitable container, such as a test tube
- Use an insulation
- Add 50 ml of water to the test tube
- Using a thermometer measure the initial temperature of the water
- Add 1g of ammonium to the test tube with water, and stir to dissolve the solid
- Using a stopwatch let the solution react for 5 minutes
- Measure the final temperature of the solution
- Calculate the temperature differences
- Repeat with different masses
- Repeat with the same volume of water
What order did scientists used to arrange elements in early periodic table?
By their atomic weight
In the early periodic table some elements were placed in the wrong groups.
Mendeleev overcame this in his PT.
Give one way Mendeleev did this.
Left gaps
Why is electrolysis use to extract some metals?
Metal is too reactive to be extracted using carbon
Aluminium is produced by electrolysis of a molten mixture.
What two substances does the molten mixture contain?
- Aluminium oxide
- Cryolite
Explain why sodium is less reactive than potassium
Sodium has fewer energy shells, so the outer electron is closer to the nucleus, so greater attraction between nucleus and outer electron shell, so outer electron is less easily lost
Describe the observations made before, during and after the reaction. (Sodium+chlorine)
Before - Green gas
During - Yellow flame
After - White solid
Oxygen is formed at the positive carbon electrode in a specific reaction. Explain why the positive carbon electrode must be continually replaced.
At high temperatures, oxygen reacts with carbon so the positive electrode burns to produce carbon dioxide.
C + O2 - CO2
What are the free moving particles in a:
- Carbon electrode
- Molten mixture of aluminium oxide and cryolite
- Metal wire
Carbon electrode - Delocalised electron
Molten mixture of aluminium oxide and cryolite - Ions
Metal wire - Delocalised electrons
Explain what happens to caesium atom and to oxygen atom when caesium reacts with oxygen to produce caesium oxide.
Caesium atom loses one electrons, and oxygen atom gains two electron.
So two caesium atoms react with one oxygen atom to form C+ and O2-
Explain why caesium is more reactive than sodium.
Caesium has more shells, so the outer electron is further from the nucleus, so there is a weaker attraction between nucleus and outer electron, so outer electron is more easily lost.
Explain why the early periodic tables placed iodine before tellurium, but then Mendeleev placed tellurium before iodine.
Early periodic tables were arranged with elements in order of their atomic weights.
Iodine has a lower atomic weight than tellurium, so Mendeleev placed iodine with elements with similar properties
1 g = ______ mg
1g = 1000mg
1dm3 = _______ cm3
1dm3 = 1000cm3
Describe how Mendeleev’s periodic table was different to Newland’s
The Mendeleev’s periodic table arranged the elements with similar chemical properties into columns, and he also left gaps for future elements
Explain why Mendeleev’s version of the periodic table became more widely accepted than Newland’s
Over time elements were discovered, which filled the gaps
Why does the reactivity increases as you go down group 1?
The number of shells will increase, so the outer-most electron (-ve) is further from the nucleus (+ve), and as the nucleus is the only force holding the electron, as the electron is further from the nucleus the attraction force between the electron and the nucleus weakens, so the electron is easily lost.
Explain why the boiling point increases as you go down group 7
The molecules get larger down the group, so the intermolecular forces get stronger, so more energy is needed to overcome the forces of attraction between molecules.
What is the meant by mixture?
Two or more substances, that are not chemically bonded together.
