Chem 1 Lab Final
A solution is made by dissolving 5.4893g of CuSO₄ in sufficient water to form exactly 100.00mL of solution. Find the moles of CuSO₄ (159.6g/mol) in the solution.
5.4893g(1mol/159.6g) = 0.034394 mol
7.68*106= what (in correct significant figures)?
814
What type of reaction is: Pb(NO₃)₂(aq) + 2NaCl(aq) → PbCl₂(s) + 2NaNO₃(aq)
Double replacement reaction
Delta H is positive
Endothermic reaction
Heat is absorbed
Endothermic reaction
Temperature of the flask decreases
Endothermic reaction
Delta H is negative
Exothermic reaction
Heat is released
Exothermic reaction
Temperature of the flask increases
Exothermic reaction
What elements are halogens?
Fluorine, Chlorine, Bromine, Iodine, and Astatine
What type of reaction is: 2HNO₃(aq) + K₂CO₃(aq) → 2KNO₃(aq) + H₂O(l) + CO₂(g)
Gas forming reaction
Strong acids
Hydrochloric acid, sulfuric acid, and perchloric acid
Derive the net ionic equation for the reaction of acetic acid (CH₃COOH) and sodium hydroxide.
H⁺(aq) + OH⁻(aq) → H₂O(l)
Derive the net ionic equation for the reaction of hydrochloric acid and barium hydroxide.
H⁺(aq) + OH⁻(aq) → H₂O(l)
Why is water added to the crucible after the crucible is cooled in lab 4?
In the first burn, magnesium oxide and magnesium nitride are created because of the nitrogen in the air. Adding water and burning the magnesium sample again helps the magnesium nitride become magnesium oxide.
What elements are alkali metals?
Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium
Explain the difference between density and mass.
Mass is the composition of matter where density explains the concentration of mass.
Calculate the molarity (mol/L) of a 250.0mL solution made by diluting 6.74mL of 12.1M potassium hydroxide with deionized water.
M₁V₁ = M₂V₂ (12.1M)(6.74mL) = (M₂)(250.00mL) M₂ = 0.326M
What is the oxidation state of each element in NO₂(g)?
N = 4+ and O = 2-
HNO₃ is called?
Nitric acid
What aqueous metals react with Fe(s)?
Ni²⁺ and Cu²⁺
List 3 out of the 4 indications that a chemical reaction has occurred.
Permanent color change, a solid formed (precipitate), a heat change was observed
What type of reaction is: Cu(s) + 2AgNO₃(aq) → Cu(NO₃)₂(aq) + 2Ag(s)
Single replacement reaction
NaNO₃ is called?
Sodium Nitrate
ZnSO₄ is called?
Zinc Sulfate
Define what a Lewis Structure is
a representation of the electrons of an element that are able to be covalently or ionicly bonded. They are the outermost electrons of the element (valence electrons).
CuSO₄ is called?
Copper (II) Sulfate
How many significant figures in 0.1234?
4
How many significant figures in 0.3045?
4
How many significant figures in 272.0?
4
Calculate the percent composition of chloride if the total mass of the mixture was 2.7123g and after separation and drying the mass of the chloride was 1.423g.
(1.423g/2.7123g)*100 = 52.46% chloride
For a particular reaction, you calculate the theoretical yield to be 4.8765g. The final product actually weighed 4.0542g. What is the percent yield?
(4.0542g/4.8765g) * 100 = 83.137%
What is the oxidation state of Cu(s)?
0, solids have a zero oxidation state
A solution is made by dissolving 5.4893g of CuSO₄ in sufficient water to form exactly 100.00mL of solution. Determine the molarity (mol/L) of the solution.
0.034394mol/0.1L = 0.34394mol/L
Determine the number of moles of magnesium in a strip of magnesium with a mass of 0.3546g. The molar mass of magnesium is 24.305g/mol.
0.3546g(1mol/24.305g) = 0.01459 mol
Determine the number of moles of aluminum in a strip of aluminum with a mass of 0.483g.
0.483g(1 mol/26.98g) = 0.0179 mol
Ethylene glycol (used as antifreeze) had a density of 1.11g/cm³. What is the volume in L of 5.2kg of this liquid?
1.11g/cm³ = 5.2kg/V = 4.7L
Ethylene glycol (used as antifreeze) had a density of 1.11g/cm³. What is the mass in grams of 271 mL of ethylene glycol?
1.11g/cm³ = m/271mL = 301g
A titanium bicycle frame displaces 0.415 L of water and has a mass of 1.86kg. What is the density of the titanium in g/cm³?
1.86kg/0.415L(1g/0.001kg)(1L/1000ml) = 4.48 g/cm³
Determine the molar mass (g/mol) of Nickel (II) chloride (NiCl₂)
129.6g/mol
A sample of copper weighs 16.82g and has a volume of 3.2cm³. Calculate the density of copper in g/cm³.
16.82g/3.2cm³ = 5.3g/cm³
Determine the molar mass (g/mol) of water
18.02g/mol
A perfect cube of aluminum metal was found to weigh 19.8799g. If the density of aluminum is 2.70 g/mL, what are the dimensions of the cube?
2.70g/mL = 19.8799g/V = 7.36mL ³√7.36cm³ = 1.95cm * 1.95cm *1.95cm
How many significant figures in 0.00768?
3
How many significant figures in 1050?
3
How many significant figures in 3.56x10⁴?
3
Calculate the molarity (mol/L) of a 250.0mL solution made from 3.2410g of lithium hydroxide and deionized water (molar mass of LiOH is 23.95g/mol).
3.2410g(1mol/23.95g) = 0.13532 mol M = 0.13532mol/0.2500L = 0.5413M
342.7+12.35+7.238 = what (in correct significant figures)?
362.3
What is the chemical formula for silver nitrate?
AgNO₃
What is the name of the group that Na belongs to on the periodic table?
Alkali metals
What property are the elements in the periodic table arranged by?
Atomic number
List one similarity and one difference between gravity filtration and vacuum filtration.
Both use a filter to separate a solution. Gravity filtration does this by allowing gravity to pull the solution through the filter while vacuum filtration uses vacuum power to pull the solution through.
Determine the empirical formula for C₈H₈
CH
Determine the empirical formula for C₂H₆O₂
CH₃O
Give the formula for calcium carbonate and determine if it is soluble or insoluble in water from the Solubility Rules.
CaCO₃ is insoluble
Strong bases
Calcium hydroxide, lithium hydroxide, and sodium hydroxide
Name the 7 general types of reactions
Combination, decomposition, combustion, single-replacement, double-replacement, gas-forming, and neutralization
Why should you minimize your contact with the coffee cup calorimeter?
Contact should be minimized to reduce error in temperature readings from heat absorbed from your hands.
Cu(OH)₂ is called?
Copper (II) Hydroxide
CuO is called?
Copper (II) Oxide
How do you determine how many valence electrons an atom has?
The easiest way is to see which group on the periodic table the element falls on. Na has 1 and O has 6.
Why are flame tests use to identify the alkali metals in alkali-containing compounds?
The oxygen in the combustion reaction causes the alkali metals to burn in different colors.
Define the term limiting reactant.
The reactant that is used up completely in a reaction before the other reactants. The product is limited by the amount of this reactant.
Explain why a student needs to dry a sample of filtered sand and water before weighing it on a balance. What would happen to your calculations if you didn't dry the sample?
The sample must be dry to eliminate the mass of the water from the sand. If the sample wasn't dry, the calculations would include the mass of both the sand and some water, making the calculations inaccurate.
Which of the following would give you the most precise volume? beaker, graduated cylinder, or volumetric pipet
Volumetric pipet
A solution is made by dissolving 5.4893g of CuSO₄ in sufficient water to form exactly 100.00mL of solution. Identify the solute and the solvent.
Water is the solvent and CuSO₄ is the solute
List three safety precautions a student must use while working in the lab.
Wear closed toed shoes, wear goggles, and no horseplay.
Which is the most precise: a decigram, centigram, or analytical balance?
analytical balance
An empty graduated cylinder weighs 64.50g. To this was added 32.0mL of water. The density of water is 1.00g/mL. An irregular piece of lead is submerged in the water, bringing the total volume to 57.4mL. The mass of the cylinder and all of the contents was 406.50g. Calculate the density of the lead.
d=m/v so... v = 57.4mL-32.0mL = 25.4mL m = 406.50g-64.50g-32g = 310g d = 310g/25.4mL = 12.2g/mL
Give two examples of a homogeneous mixture.
laundry detergent and a cup of coffee
What is the basic units for the following physical quantities? length mass temperature
meter (m) gram (g) Kelvin (K)