1.6 QUANTIFYING ELEMENTS & COMPOUNDS Flashcards
Are zeros between other non zero digits significant?
YES. zeros in between other non zero digits are always significant
Do we use the relative atomic mass or the atomic number to measure mole?
The relative atomic mass (u)
Are trailing zeros at the end of a number that contains a written deicimal point significant?
2.035264000
YES!
0’s at the end of a number WITH a written decimal point are ALWAYS significant
For example: sodium (Na) has a mass of 22.99u, which means one mole of Na is?
One mole of sodium is 22.99g
22.99g = 6.02 x 10^23
Write the scientific notation for:
0.0000516
5.16 x 10^-5
What does n in M x 10^n represent?
n is the number of decimal places to be moved and the direction in which it moves.
Why do we use moles?
Used to measure compounds and elements so we can get the exact amount of particles involved in chemical reactions.
Also used because particles are very small and need a large number to represent it accurately.
What is molar mass?
Molar mass is defined as the mass in grams of one mole of a substance. The units of molar mass are grams per mole, abbreviated as g/mol.
What does a positive ^n indicate for a number in standard form?
This indicates that this is a large number
4.35 x 10^16 = 43 500 000 000 000 000
What are base units?
m/s/mol
What is the particle entitiy for ionic compounds?
Formula Units
What is the pre-fix for 10^2
hecto
What is the formula for scientific notation?
M x 10^n
Are zeros at the front of a number significant?
0000056983.254
NO. zeros at the front of a number are never significant
Equation for:
Number of Particles =
Number of particles = number of moles × Avogadro’s number
or
N = n × NA
What does a negative ^n indicate in standard form?
It indicates that the number is small.
0.00000632 = 6.32 x 10^-6
What is the prefix for 1 x 10^-9?
nano
What are the rules of significant digits?
What is Avogadro’s Number?
Avogadro’s Number is the name of a measurement used to represent 6.02 x 10^23 of something. It is used to show how large of an amount there is.
What is the symbol for mole?
(n), not exponent ^n in scientific notation
What are the entities of a molecular compound?
molecules
What direction does the decimal in a negative n move?
The decimal moves to the left, making the number smaller
5.648 x 10^-8 = 0.00000005648
What is Avogadro’s Number equal to?
Avogadro’s Number is equal to one mole.
For example: one mole of iron is 6.02 x 10^23 of iron atoms.
What is a significant figure/digit?
A sig figure/digit is something that is actually measured.
When taking the atomic relative mass to measure molar mass, how many digit places do we round to?
the nearest hundredth.
For example Oxygen has mass of 15.99amu
This becomes 16.00g/mol
What is the difference between molecular mass and molar mass?
Molecular weight is the mass of a molecule of a substance. It can also be called molecular mass. … Molar mass is the mass of one mole of a substance. Molar mass is reported in grams per mole or g/mol
What direction does the decimal move in a positive n?
The decimal moves to the right.
5.436 x 10^8 = 543 600 000.
What is the particle entity for elements?
atoms.
In Scientific Notation, what numbers does M in M x 10^n have to be between?
where 1 lesser or equal to M lesser than 10.
What is the name of the atomic amount used to measure chemical quantities?
a mole
What is molar mass of a molecule?
Sum of the individual molar masses of the atoms in the mole.
For Example: one H2O
2 Hydrogen: 2 x 1.01u = 2.02u
1 oxygen: 1 x 16.00 = 16.00u
2.02u + 16.00u = 18.02g/mol
Write the scientific notation for:
0.698534 x 10^9
698 534 000
What equation do you use to find the Molar Mass?
M = m/n
molar mass (g/mol) = mass (g) / number of mols (mol)
