Formula Fixation
How would you determine the number of neutrons in an atom?
Mass number - atomic number
What is the mass % of carbon in CH4?
75%
When metals forms ions, they’re usually _______.
Cations
What is the molarity of 1 mole of solute in 1 L of solution?
1 M
Define a precipitation reaction.
A reaction that results in the formation of solid when an insoluble ion species in combined in solvent.
What makes a compound organic?
Contains carbon and usually hydrogen (example: CH4)
What is the mass % of carbon in C11H17N3O8?
41.37%
What charge does a Group 2 atom typically form?
+2
What volume of solution (in L) is needed to dilute 2 M to 1 M for 500 mL?
0.250 L
Insoluble substances only dissolve up to ___ M.
0.1 M
What are metalloids and where are they approximately located on the periodic table?
Have metal appearance but can behave chemically as either a metal or nonmetal
Located on stair-step boundary between metals and nonmetals
What the volume of 0.050 M NaOH solutions that contains 0.025 mol NaOH?
0.050 L
What is the charge of a sulfate ion?
-2
What’s the molarity of a solution if you dissolve 5 grams of HCl in 250 mL of water?
0.55 M
Define theoretical yield.
The amount of product formed (yield) when we assume the reaction goes to completion.
What is the rule for sig figs when dealing with an addition/subtraction problem?
The answer must have the same number of decimal places as the limiting term
How many molecules of CO2 are in 10 grams of CO2?
1.37 x 10^23 molecules of CO2
What is the name of this compound? HSO3-
Hydrogen sulfate
What is the empirical formula of a compound that contains 40% carbon, 6.67 % hydrogen, and 53.3% oxygen by mass?
CH2O
94% yield of iron in reaction. How many grams of iron produced in experiment if theoretical yield was 134.5 grams?
126.43 grams
What is the difference between accuracy and precision?
Accuracy: how close measured value is to actual (random error)
Precision: how close series of measurement are to another (systematic error)
Which would contain the least number of molecules and why?
20.0 g of H2O (18.02 g/mol)
77.0 g of CH4 (16.06 g/mol)
68.0 g of CaH2 (42.09 g/mol)
100.0 g of N2O (44.02 g/mol)
84.0 g of HF (20.01 g/mol)
20g of H2O
Name the compound formed between potassium and oxygen.
Potassium oxide (K2O)
You have 1.00 L of 6.00 M HCl solution. You take 250mL of sol’n and dilute with water to final volume of 1.00 L. What’s the new molarity?
1.50 M
Potassium iodide + silver nitrate → _____ + _____ Finish equation and determine precipitate.
KI(aq) + AgNO3(aq) KNO3(aq) + AgI(s)