Chemistry May 2015 Flashcards
What is precipitation?
Precipitation is when a solid is formed when two solutions are mixed.
What is the equation for average rate of reaction?
Average rate of reaction: change of quantity/ change in time
Describe the atom.
The atoms has a very small positively charged nucleus with negatively charged electrons moving around outside the nucleus.
Describe the location and charge of the three sub-atomic particles.
Protons- nucleus, 1+
Neutrons- nucleus, neutral (0)
Electrons- electron cloud, 1-
What is the relative mass of the proton, neutron and electron?
Proton- 1
Neutron- 1
Electron- Negligable
Ifsodium, Na, has an atomic number of 11 and mass number of 23 and has no overall charge, can you calculate the number of each sub-atomic particle?
Proton- same as atomic number, 11
Neutron- mass number-atomic number, 12
Electrons- no overall charge, 11
What is an ion?
An atom which has lost or gained electrons.
When are ions formed?
Ions are formed when atoms gain electrons to make negative ions or when atoms lose elctrons to form positive ions
If chlorine, Cl has an atomic number of 17, a mass number of 35 and a negative overall charge (Cl-), including ions, calculate the number of each sub-atomic particle?
Protons- gained negative charge (not positive), 17
Neutrons- mass- atomic, 18
Electrons- gained electron (negative charge), 18
What is an isotope?
Isotopes of an element are atoms with the same number of protons but a different number of neutrons. (same atomic number but different mass number).
What is a common isotope?
Chlorine with an atomic number of 17 but mass numbers of 35 and 37.
What happens in a covalent bond?
Two positive nuclei are held together by their common attraction for shared pair of electrons
Learn how to draw a diagram to show how the outer electrons form a covalent bond.
- check jotter or summary notes- middle page.
What do ionic structures consist of?
Ionic structures consist of a giant lattice of oppositely charged ions.
Why don’t covalent substances conduct electricity?
Covalent substances do not conduct electricity since they are made up of molecules which are uncharged.
Why are formula equations balanced? (what does this show)
Formula equations can be balanced to show the relative number of moles of reactants and products.
What is the gram formula mass of any substance known as?
The Mole
What is the effect of dilution on the pH of an acid?
Diluting an acid will reduce the concentration of the H+ ions (hydrogen ions) , which increases the pH.
What is the effect of dilution of the pH of an alkali?
Diluting an alkali with reduce the concentration of the OH- ions (hydroxide ions), which decreases the pH.
What are the bases used to neutralize acidic solutions?
Reactive metals (MAZIT), metal oxide, metal hydroxide and metal carbonate
What is a spectator ion?
A spectator ion is present during a chemical reaction but does not take part in the reaction.
What is the equation for neutralisation with metal oxide?
Metal oxide + acid ———> salt + water
What is the equation for neutralisation with reactive metals?
‘MAZIT’ metal + acid ——–> salt + hydrogen
What is the equation for neutralisation with metal carbonate?
Metal carbonate + acid ——–> salt + carbon dioxide + water
What is the equation for neutralisation with metal hydroxide?
Acid + metal hydroxide (Alkali) ——–> salt + water
What shape of molecule is water? H20
bent, angular or v-shaped (check jotter for diagram)
What shape of molecule is ammonia? NH3
Pyramidal (check jotter for diagram)
What shape of molecule is methane? CH4
Tetrahedral (check jotter for diagram)
What kind of solution does soluble metal oxides form?
Soluble metal oxides for alkaline solutions.
What is the equation for titration?
C1 x V1/ n1 = C2 x V2/ n2
How do you calculate the average burette reading?
Take an average of all titrations that took place.
