Formulae, equations and amount of substance

Question 1

what is the relative charge for protons neutrons and electrons

Answer 1

protons–> +1
neutrons–> 0
electrons–>-1

atomic number, mass number

Question 2

what is the relative mass for protons neutrons and electrons

Answer 2

protons–>1
neutrons–>1
electrons–>1/2000

atomic number, mass number

Question 3

what are negative charges mean for ions?

Answer 3

theres more electrons than protons(number + minus )–> more electrons

Question 4

what do positive charges mean for ions and give an example?

Answer 4

positve charges meant that there is more than protons than electrons –>eg magnesium which is in group 2 has 2+ charge . Proton number/atomic is 12 therefore the electron number must be 10

Question 5

what are isotopes?

Answer 5

elements with the same number of protons but different number of neutrons

Question 6

what is relative atomic mass(Ar)?

Answer 6

weighted mean mass of an atom of an element compared to 1/12th of the mass of an atom of carbon 12.

relative atomic mass

Question 7

what is the relative molecular mass(mr)?

Answer 7

weighted mean mass of a molecule compared to the mass of 1/12th of the mass an atom of carbon 12

relative molecular mass (Mr)

Question 8

what is the relative isotopic mass ?

Answer 8

mass of a atom of an isotope compared to 1/12th of the mass of carbon 12.

relative isotopic mass

Question 9

what is avogadros number for and what is the number?

Answer 9

avogadros number is measuring the amount of a substance and the number is 6.02x 10^23

Avogadro constant

Question 10

how do you find the number of particles of a substance ?

Answer 10

number of particles=avogadros constant x number of moles

Question 11

how can you find the number of moles?

Answer 11

moles= mass/mr

Question 12

h

how do you find moles in soloutions?

Answer 12

moles =concentration (moldm-3) x volume(dm^3)

Question 13

do isotopes have the same chemical and physcial property and why?

Answer 13

isotopes have the same chemical propery because its dependent on **number/arrangement **of electrons and isotopes have the same number of electrons.
isotopes have dofferent physical properties because its dependent on mass number and isotopes hae same atomic number but different mass number.

Question 14

what makes up most the mass/volume of a atom

Answer 14

mass–>nucleus
volume–> empty space

Question 15

what are ionic equations?

Answer 15

equations that show the ions formed in a soloution and which particles are reacting

balanced full and ionic chemical equations,
including state symbols

Question 16

at

what are spectator ions ?

Answer 16

they are ions are on both sides of the ionic equations and are NOT involved in the reaction

balanced full and ionic chemical equations,
including state symbols

Question 17

$$$is water an ion and why?

Answer 17

NOT an ion and ions are only only acids bases and salts

balanced full and ionic chemical equations,
including state symbols

Question 18

how do you find the theoretical mass of a substance

Answer 18

-balence equation
-find mr of each species
-perform mass= moles x mr (using moles as balencing number)
-form it into a ratio and dividing each side by the smallest mass
-times each side by the given quantity

masses of substances

Question 19

what is emperical formula?

Answer 19

the simplest ratio of elements in a compound

empirical
and molecular formulae

Question 20

how do you find the emperical formula of a compound?

Answer 20

-substitute percentage/ value in a ratio with elements
-divide each element by the mr of each(as if moles=mass/mr)
-divide ALL answers by the smallest amount of moles
-substitute the answer to the emperical formula

empirical and molecular formula

Question 21

how do you find molecular formula of a substance?

Answer 21

-write down and substitute percentage/masses of each compound
-divide compounds by mr as if moles=mass/mr
-see the element wanted and times or divide the answer of compound by moles/atoms
-divide the recent answers by the smallest number
-substitute back in

empirical

Question 22

how do you find percentage compostition state the formula

Answer 22

percentage mass= total ar of desired element/mr of whole compound x100
eg Find the percentage of calcium in calcium carbonate, CaCO3.

Question 23

how do you find out the value of water of crystallisation?

Answer 23

heat an a hydrated salt to remove water of crystallisation to form a anhydrous salt

Question 24

how do you find out water of crystallistion with calculations?

Answer 24

-put the hydrated and anyhrated salts in a ratio
-use moles=mass/mr
-divide by the smallest answer of moles
-substitute the answeer in the compound to find x

Question 25

what is the equation for percentage yield?

Answer 25

actual yield/theoretical yield
x100

Question 26

what is theoretical yield?

Answer 26

amount of a product produced assuming no products have been lost AND reactants have rected fully

Question 27

whats the equatuon for more concentrated soloutins?

Answer 27

volum use=final concentration divide by initial conc x volume reqiured