ch 6- quantifying atoms and compounds

Question 1

What is an isotope(n.)

Answer 1

Atoms of the same element that have a different mass due to a different number of neutrons.

Question 2

Relative isotopic mass Ir(n.)

Answer 2

Relative isotopic mass Ir(n.)=The mass of the isotope on the scale in which the relative isotopic mass of a carbon-12 atom is assigned a value of 12 exactly.

-Relative isotopic mass is the mass of a single isotope with a specific mass of an element.
-The relative isotopic abundance is the percentage of atoms with a specific atomic mass found in a naturally occurring sample of an element

Question 3

Is there units in relative mass

Answer 3

there are no units because it is a relative mass.

Question 4

Is the relative atomic mass on the periodic table.

Answer 4

The relative atomic mass is on the bottom of elements on periodic table

Question 5

Relative atomic mass Ar(n.)

Answer 5

Weighted average of the masses of an element’s isotopes on a scale on which the mass of a carbon-12 atom is assigned a value of 12 exactly.

Question 6

Relative atomic mass formula

Answer 6

Relative atomic mass Ar formula=
Ar=Σ(%abundance x Ir)/100

-Ar=Relative atomic mass
-Ir=relative isotopic mass

Question 7

Relative molecular mass Mr(n.)

Answer 7

Weighted average of a molecule’s masses of the formula units on a scale on which the mass of a carbon-12 atom is assigned a value of 12 exactly.

Question 8

Relative molecular mass formula/relative formula mass

Answer 8

Relative molecular mass formula/relative formula mass e.g. Of carbon monoxide=
Mr(CO)=Ar(C) + Ar(O)
Mr(CO)=12.0 + 16.0
Mr(CO)=28.0 no unitsss.

Question 9

What is mass spectrometry(n.)

Answer 9

Analytical technique used to measure the mass of ions relative to their charge

:in mass spectrometry, a sample of an element is put into a mass spectrometer. The output is a mass spectrum.

Question 10

What are the features of a mass spectrum graph(AKA a mass spectrograph, but don’t quote me on it hahahaha)

Answer 10

A mass spectrum=
:Y axis= Relative abundance(%)
:X axis=Mass-to-charge ration (m/z)
:each individual peak represents a new isotope of an element or element all together.

Question 11

-Mass-to-charge ratio m/z(n.)

Answer 11

The mass of an ion divided by its charge.

Mass-to-charge ratio is shown as m/z but is sometimes seen as m/e^-

Question 12

Mole(n.)

Answer 12

6.02x10^23 entities

Moles is represented as NA

Question 13

Entities(n.)

Answer 13

Atoms, molecules, compounds, ions, electrons.

Question 14

What is moles unit

Answer 14

mol

Question 15

Avogadro’s constant, NA(n.)

Answer 15

The number of atoms in exactly 12g of C-12, 6.02 x 10^23 mol^-1

Question 16

Relationship of mol to Avogadro’s constant formula

Answer 16

Relationship of mol to Avogadro’s constant(formula)
N=N/NA

-Where:
-n=amount of substance in mole (mol)
-N=number of particles e.g. atoms, molecules, ions, electrons
-NA=Avogadro’s constant, 6.02 x 10^23

Question 17

Density formula

Answer 17

Density= mass/volume

Or

d=m/v

Question 18

Relative molecular mass(n.)

Answer 18

Weighted average of a molecule’s masses of the formula units on a scale on which the mass of a carbon-12 atom is assigned a value of 12 exactly.

Question 19

Molar mass(n.)

Answer 19

the mass in g of one mol of substance, g mol^-1

Question 20

Relative molecular mass formula

Answer 20

Relative molecular formula e.g. Of water
Mr(H2O)=Ar(2xH) + Ar(1xO)
Mr(H2O)=(2x1.0) + (16.0X1)
Mr(H2O)=18.0 no unitsss

Question 21

Molar mass formula

Answer 21

Molar mass formula e.g. Of water
Mr(H2O)=M(2xH) + M(1xO)
Mr(H2O)=(2x1.0g mol^-1) + (1x16.0g mol^-1)
Mr(H2O)=18.0g mol^-1

Question 22

Relative molecular mass symbol

Answer 22

Mr

Question 23

Molar mass symbol

Answer 23

M

Question 24

Units of relative molecular mass

Answer 24

No units

Question 25

Units of molar mass

Answer 25

The units of molar mass are g mole^-1

Question 26

Relationship of mass to mole(formula)

Answer 26

Relationship of mass to mole(formula)
N=m/M

-n=amount of substance, in mole (mol)
-m=mass, in grams, g
-M=Molar mass, g mole^-1

Note=use molar mass instead of relative molecular mass when calculating the amount of substance in mol.

Question 27

Percentage composition(n.)

Answer 27

Percentage by mass of an element in a compound.

Question 28

Formula for percentage composition by mass

Answer 28

Percentage composition by mass(formula)
Compound=(Molar mass of element/Molar mass of compound)X100

Question 29

Steps for calculating percentage composition

Answer 29

Relationship between the number and amount of particles

When solving problems use these following problem-solving strategies:
1)Underline key information in the stem of the question
2)What is the question asking you to find or calculate
3)Which equation should you use?
4)Do you need to transpose the equation?
5)Substitute in the values
6)Report you answer to the appropriate number of significant figures

Question 30

Empirical formula(n.)

Answer 30

The simplest ratio of elements in a compound.

empirical formula also abbreviated to (EF)

Question 31

What does empirical mean

Answer 31

by experiment’

Question 32

Molecular formula(n.)

Answer 32

The actual number of atoms of each element in a molecule.

Question 33

What are the steps to determine the molecular formula

Answer 33

Steps to determine the molecular formula=
-If you know the molar mass and the empirical formula of the molecule, you can determine the molecular formula using the following steps.=
1)Determine molar mass of EF
2)Divide the molar mass of the molecule by the molar mass of EF
3)Multiply the EF by the number obtained in step 2