Chemical literacy

Question 1

what are the SI units?(Système International
d’Unités)

Answer 1

system of internationally standardised and
recognised units of measurement

Question 2

what are core units?

Answer 2

mutually independent and form the basis of the SI
system

Question 3

What are the seven core units?

Answer 3

mass (g), length (m), time (s), electrical current (A), temperature (K), amount of substance (mol), light intensity (cd)

Question 4

What are derived units?

Answer 4

Derived units are defined in terms of the seven core units via a system of equations

Question 5

what derived units for area, volume, concentration, density, electrical charge, energy and frequency?

Answer 5

area- m2
volume- m3
concentration- mol dm-3
density- kg m-3
electrical charge- A s
energy- kg m2 s-2
frequency- s-1

Question 6

what is the unit symbol and name for concentration?

Answer 6

symbol- M
name- Molar

Question 7

what is the unit name and symbol for electrical charge?

Answer 7

symbol- Coulomb
symbol- C

Question 8

what is the unit name and symbol for energy?

Answer 8

name- joule
symbol- J

Question 9

what is the unit name and symbol for frequency?

Answer 9

name- Hertz
symbol- Hz

Question 10

What are the names, symbols with factors (10 to the power of…) of all the accepted multipliers from biggest to smallest?

Answer 10

tera T (12), giga G (9), mega M (6), kilo k (3), hecto h (2), deca da (1), deci d (-1), centi c (-2), milli m (-3), micro u (-6), nano n (n), pico p (-12), femto f (-15), atto a (-18)

Question 11

The litre is not apart of the SI but it is very widely used so how do you convert litres, L, into the SI units (meters)?

Answer 11

1L = 1dm3

Question 12

what is 1mL in L and in SI units?

Answer 12

1mL = 10-3L = 1cm3 (SI units)

Question 13

what is 1000 L in SI units?

Answer 13

1m3

Question 14

what is 1M in units of concentration, mol dm-3 and mol L-1?

Answer 14

1 M = 1 mol dm-3 = 1 mol L-1

Question 15

What is the difference between Molar and mole?

Answer 15

-Molar is the unit of concentration (symbol M)
-Mole is the unit of amount of substance (symbol mol)
-1M = 1mol L-1

Question 16

What is the definition of elements?

Answer 16

the simplest type of pure substance, made entirely of one type of atom; they can not be broken down into simpler substances

Question 17

what is the definition of atoms?

Answer 17

the building blocks of matter, the smallest
amounts of an element that still have all the properties of the element

Question 18

what is the definition of a molecule?

Answer 18

two or more atoms chemically joined
together
– Molecules that contain more than one element are also referred to as ‘compounds’

Question 19

what is the mass number of an atom?

Answer 19

total number of protons and neutrons in the nucleus

Question 20

what is the atomic number?

Answer 20

number of protons (= number of electrons)

Question 21

what are isotopes?

Answer 21

elements with the same atomic number but different mass number

Question 22

what is the unified atomic mass unit?

Answer 22

1/12th of the mass of the C12 atom, symbol u (italics). It is a relative unit.

Question 23

Avogadro constant definition?

Answer 23

number of atoms in exactly 12g of C12

Question 24

what is the value for one atomic mass unit?

Answer 24

• 1 mol of 12C has a mass of 12 g
• There are NA (6.022 x1023) atoms in 12 g of 12C
• Therefore, 1 atom of 12C has a mass of 12 / NA = 19.92 x 10-27 kg
• 1 atomic mass unit = 1/12th of the mass of 1 atom of 12C = 1.66 x 10-27 kg

Question 25

prove that the atomic mass and molar mass are the same value using the example of oxygen

Answer 25

• The mass of 1 oxygen atom is 1.66 x 10-2 7 x 16 = 26.56 x 10-2 7 kg
• 1 mol of oxygen atoms weighs 26.56 x 10-2 7 x NA = 16 g (Molar mass)

Question 26

what is the relative molecular mass (Mr)?

Answer 26

the sum of the relative atomic masses of the atoms that make up the molecule
* The Mr gives the mass (in grams) of 1 mole of substance (Molar mass)