Atomic structure Flashcards

Question

equation for relative atomic mass

Answer 1

sum of ( isotope abundance x isotope mass number) / sum of abundances of all the isotopes

Answer 2

use evaporation if the salt doesnt decompose, if it does, use crystalisation

Answer 3

- pour the solution into an evaporating basin - heat the solution, it will get more concentrated# - once some of the solvent has evaporated, or once crystals have began to form, remove the dish from the heat and allow it to cool - the salt should start to form crystals as it becomes insoluble in the cold, highly concentrated solution - filter the crystals out of the solution, and leave them in a warm place to dry

Answer 4

- salt dissolves in water, but sand doesnt, so first 1. Grind the mixture to make sure the salt crystals are small, so will dissolve easily 2. Put the mixture into water and stir, the salt will dissolve but the sand wont 3. filter the mixture, the grains of sand wont fit through the tiny holes in the filter paper, so they collect on the paper instead. The salt passes through the filter paper as its part of the solution 4. Evaporate the water from the salt so that it forms dry crystals

Answer 5

- we place our solution in a flask with the liquid and dissolved solid - this flask is connected to a continuous glass tube - the glass tube is surrounded by a jacket called a condenser - cold water from the tap continuously runs through the condenser - after running through the condenser, the water simply goes down the sink

Answer 6

it keeps the internal glass tube cold

Answer 7

1. start by heating your solution with a bunsen burner 2. as we heat the liquid, it begins to evaporate, turning into vapour 3. the vapour rises up the glass tube 4. the vapour then passes into the condenser 5. the vapour then condenses back into a liquid as it passes through the condenser 6. we are left with crystals of the solid in the flask, and liquid collected in a beaker

Answer 8

- the flask containing our liquids with different boiling points is connected to a long column containing glass beads called the fractionating column - thermometer at the top of the fractionating column - condenser and beaker under it

Answer 9

1. gently heat the mixture 2. both liquids will start to evaporate, but the one with a lower boiling point will evaporate more easily 3. we have a mixture of two different vapours making their way to the fractionating column 4. when they reach the fractionating column, they condense and drip back into the flask, where they evaporate again 5. this repeated evporation and condensation increases the amount of the chemical with a lower boiling point in the fractionating column 6. the vapours pass along the condenser and turn into a liquid, but the liquid still contains both chemicals - at one point, the thermometer reaches the temp of boiling point of the chemical with the lower boiling point, and it stops rising, and its mostly the chemical passing through the condenser so we can collect it - the thermometer temp begins to rise again, but then its mostly the chemical with the higher boiling point, so we can collect that

Answer 10

the thermometer's temperature remains constant