test feedback revision Flashcards
Which changes of state need energy?
Melting, evaporating and sublimation
What is an atom?
Simplest thing that can exist on its own
What is a molecule?
2 or more atoms joined together by covalent bonds
What is an ion?
Charged particle
What is a mixture?
2 or more substances not chemically joined together
Describe the structure of the atom
Nucleus that contains protons and neutrons with electrons in shells orbiting it
What is the mass of a proton? neutron? electron?
P= 1, n = 1, e 1/1840 or negligible
What are the charges on a proton? neutron? electron?
p = +, n = 0, e = -
What does the proton number (atomic number) tell you?
Number of protons (which equals the number of electrons in an atom)
How do you work out the amount of neutrons?
Mass number - atomic number
How is a negative ion formed?
Gain an electron - non metals
What happens in an ionic bond?
Electrons are given from metals to non-metals
What happens in a covalent bond?
Electrons are shared between non-metals
Which is the stronger bond covalent or ionic?
Ionic
What are the differences between ionic and covalent compounds?
Ionic have higher mpt and bpt, are soluble in water, conduct electricity when molten, not volatile (do not evaporate easily)
What does exothermic mean?
Gives out heat or energy
What does endothermic mean?
Takes in heat
In a chemical reaction what happens?
Bonds broken (endothermic) then new bonds made (exothermic)
What is loss of oxygen in a reaction called?
Reduction
In the reaction
Ca0 + Mg = MgO + Ca
What was oxidised and what was reduced?
Ca = reduced
Mg = oxidised
What are group 1 called?
Alkali metals
What are group 7 called?
Halogens
What happens as you go down group 7?
Less reactive, more dense (more solid), darker colour
Will a reaction occur?
Sodium chloride + iodine
No as Iodine is less reactive than chlorine
Will a reaction occur?
Sodium chloride + fluorine
Yes as fluorine is more reactive than chlorine
Why are the noble gases monoatomic?
Do not react as have a full outer shell
Name the 3 acids, their formula and the salts they make
Hydrochloric HCl - chlorides
Sulphuric H2So4 - sulphates
Nitric HNO3 - Nitrates
How do you make an insolube salt?
Mix and wait till you see no more reaction then filter and the salt is in the filter paper
How do you make a soluble salt?
Mix and wait till you see no more reaction, filter then evaporate to leave the salt crystals
What does metal + acid make?
Salt + hydrogen
What does metal oxide + acid make?
Salt + water
What does metal hydroxide + acid make
salt + water
What are the properties of metals?
conductors of heat and electricity, high mpt. high bpt, malleable, ductile
What makes one metal more reactive than another
The less electrons it has to lose and how easy it is to lose them to form a positive ion
