Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
33 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
Never change subscripts when balancing an equation. True/False?
|
True
|
Changing the subscript changes the identity of the compound.
|
|
|
Balance the equation:
CH₄ + O₂ --> CO₂ + H₂O |
CH₄ + 2O₂ --> CO₂ + 2H₂O
|
|
|
|
Rules when balancing equations.
Balance which compounds/substances first? |
Balance those elements that occur in the fewest chemical formulas first
|
|
|
|
What does ∆ mean?
→ |
Addition of heat
|
The greek delta ∆ means addition of heat when over the reaction arrow → or ←
|
|
|
What type of reaction is this?
A + B → C |
A combination reaction
|
When two or more substances react to form one product
|
|
|
What type of reaction is this?
C → A + B |
A decomposition reaction
|
When one substance undergoes a reaction to produce two or more other substances.
|
|
|
Write a balanced equation for:
a) solid mercury (II) sulfide decomposing into its component elements when heated b) aluminum metal combining with oxygen in the air |
a) HgS(s) → Hg(l) + S(s)
b) 4 Al(s) + 3 O₂(g) → 2 Al₂O₃(s) |
|
|
|
What type of reaction is this?
A + B → C + D |
Combustion Reaction
|
Rapid reactions that produce a flame. In most we observe involve O₂ from the air as a reactant.
|
|
|
What are compounds that contain only carbon and hydrogen?
|
Hydrocarbons
|
hydrocarbons combusted in air react with O₂ to form CO₂ and H₂O
|
|
|
What do hydrocarbons produce when they burn in the presence of air?
|
CO₂ and H₂O
|
|
|
|
Combustion of oxygen containing derivatives of hydrocarbons, such as CH₃OH produces what?
|
CO₂ and H₂O
|
Combustion of oxygen containing derivatives will follow the same pattern of combustion.
_A + _O₂ → _CO₂ and _H₂O |
|
|
What is formula weight?
|
the sum of the atomic weights of the atoms
|
|
|
|
what is molecular weight?
|
the same as the formula weight of the molecule.
(the sum of the atomic weights of the atoms) |
|
|
|
What units are molecular weight and formula weight measured in?
|
AMU
atomic mass units |
|
|
|
what is a formula unit?
|
measures ionic substances.
ex: the formula unit of NaCl consists of one Na+ ion and one Cl- ion. So, the formula weight of NaCl is defined as the mass of one formula unit. |
|
|
|
What is the formula weight of NaCl?
Na=23.0amu Cl=35.5amu |
58.5amu
The formula weight of NaCl is defined as the mass of one formula unit. |
|
|
|
Calculating the percentage composition of any element in a substance is straight forward if the _______ _________ is known
|
chemical formula
|
|
|
|
what is the calculation for percentage composition from chemical formula?
|
%composition of element =
(number of atoms of element) x (atomic weight of element) divided by formula weight of substance x 100% |
|
|
|
What is avaogadro's number? (numerics)
|
6.02 x 10²³
|
|
|
|
define avogadro's number
|
one mole is the amount of matter that contains as many objects as the number of atoms in exactly 12g of pure ¹²C.
|
|
|
|
formula for converting moles to number of atoms?
|
(#moles) x (avogadro's number / 1 mole of compound) x
(number of atoms / 1 molecule compound) = # atoms |
|
|
|
True/False:
A mole of anything always contains the same number of particles. |
True.
A mole of eggs contains 6.02 x 10²³ eggs. A mole of elephants contains 6.02 x 10²³ elephants |
|
|
|
True/False:
The atomic weight of an element in amu is numerically equal to the mass in grams of 1 mol of that element. |
True.
Cl = 35.5 amu ⇒ 1 mol Cl = 35.5g Au = 197 amu ⇒ 1 mol Au = 197g |
|
|
|
what is molar mass?
|
the mass in grams of one mole of a substance.
(g/mol) |
|
|
|
True/Fale:
the molar mass in grams per mole of any substance is numerically equal to its formula weight in atomic mass units |
true
|
|
|
|
formula weight of NaCl is 58.5 amu . what is its molar mass?
|
58.5 amu = 58.5g/mol NaCl
|
|
|
|
formula to convert grams to moles?
|
divide grams of substance by molar mass of substance
|
|
|
|
formula to convert moles to grams?
|
multiply grams by percentage of moles
ex: 0.433 mol calcium nitrate to grams. amu=164.1g/mol 164.1g x 0.433 = 71.1g Ca(NO₃)₂ |
|
|
|
formula for converting moles to grams, and number of molecules to moles?
|
grams←(use molar mass)→moles←(use Av.'s #)→formula units
|
|
|
|
formula for calculating numbers of molecules from mass?
|
# molecules:
mass (g) / molar mass x 6.02x10²³ |
|
|
|
formula for calculating # of atoms from mass?
|
# atoms:
total # molecules x #atoms in each molecule of compound |
|
|
|
when a compound containing C and H is completely combusted, C is converted to __ and H is converted to __
|
Carbon converted to CO2
H converted to H2O |
|
|
|
the amounts of CO2 and H2O produced by a combustion reaction are determined by measuring the mass increase in the CO2 and H2O ________
|
by measuring the mass increase in the CO2 and H2O ABSORBERS
|
|
