Chemistry: Honors Midterm Review

Know the rules for significant figures. How many are in: 1.70 0.00550 20,000 10,900

1.70 has 3 significant figures 0.00550 has 3 significant figures 20,000 has 1 significant figure 10,900 has 3 significant figures

What is the volume of a liquid that has a density of 22.5 g/mL and a mass of 18.7 g?

0.831 mL

How many moles of LiBrO₃ are in 125g?

0.927 mol

Give the freezing and boiling point of water in Celcius and convert to Kelvin. (times 273.15)

0°C-freezing point 273.15°K 100°C-boiling point 373.15°K

Convert 22.5 L to mL.

1 L = 1000 mL 22.5 L = 22,500 mL

How many liters are in 12.7 kL?

1 kL = 1000 L 12.7 kL = 12,700 L

What is the molar mass of CH₄?

16g

Electron Configuration for lead (Pb)

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p²

In 2s¹, what does the 2, the s, and the 1 represent?

2 represents the level s represents the type of orbital 1 represents how many electrons in the sublevel

How many molecules are in 3.5 moles of water?

2.107*10²⁴

Subtract; 1.2 * 10 ^ 7 - 9.1 * 10 ^ 6

2.9 * 10 ^ 6

Use dimensional analysis to convert 22.5 km/hr into m/sec.

22.5 km/hr | 1000 m | 1 hr | 1 min --------------------------------------------- 1 | 1 km | 60 min | 60 sec = (22.5 ** *1000) / (60* ** 60) = 6.25 m/sec

Gaining three electrons gives what overall charge?

3-

How many particles are in 12g of H₂ gas?

3.612x10²⁴ particles

What would 38,000,000,000 be in scientific notation?

3.8 * 10 ^ 10

Draw the orbital notation for chlorine.

3p ↑↓ ↑↓ ↑ 3s ↑↓ 2p ↑↓ ↑↓ ↑↓ 2s ↑↓ 1s ↑↓

What is the density in g/mL of a substance that has a mass of 3.99 g and a volume of 0.88 mL?

4.53 g/mL

Name the following compounds: CaCl₂, CuNO₃, CCl₄, Ba(C₂H₃O₂)₂, Si₃H₈.

Calcium dichloride, copper nitrate, carbon tetrachloride, barium acetate, trisilicon octahydride

Tell the five types of reactions.

Combination/Synthesis, Decomposition, Combustion, Single Replacement, Double Replacement

What Aufbau's principle?

Electrons orbiting one or more atoms fill the lowest available energy levels before filling higher levels.

What are the differences between elements and compounds?

Element - Simplest form of matter, each represented by a chemical symbol Compound - Substance that can be separated into simpler substances only by chemical means

How do you find the number of neutrons in an atom? How many neutrons are in carbon-14?

Element's atomic mass - Element's atomic number = 14 - 6 = 8 neutrons

What is the molar mass of sodium chloride?

58.45g

How many particles are in a mole?

6.02*10²³

What would have the largest radius, carbon, a carbon cation, or a carbon anion?

A cation is the smallest, then the neutral atom, then the anion.

What is an ionic compound?

A nonmetal and a metal chemically combined

What is the empirical formula for C₃H₆O₃?

CH₂O

What shape would CO₂, CCl₄, and NH₃ be?

CO₂-linear, CCl₄-tetrahedral, NH₃-trigonal planar

What is the formula for calcium fluoride?

CaF₂

Define the law of conservation of mass

Matter is neither created nor destroyed - The combustion of a piece of paper to form ash, water vapor and carbon dioxide. In this process, the mass of the paper is not actually destroyed; instead, it is transformed into other forms.

What is the molecular formula for a compound whose empirical formula is NH₂ and has a molecular mass of 128g?

N₈H₁₆

Give an example of everyday liquids with different densities. How would they be arranged if poured together?

Oil - Least dense Water Dish soap Corn Syrup - Most dense

Define precision and accuracy.

Precision - The closeness of two or more measurements to each other Accuracy - The closeness of a measured value to a standard or known value Example (precise but not accurate) - If, on average, measurements are close to one another but are far from a known value.

What is a physical property?

Properties that can be observed without changing the composition of matter - Color - Freezing/Boiling/Melting point - Smell

What is the charge of a proton, neutron, and electron?

Proton's charge is positive Neutron's charge is neutral Electron's charge is negative

Define qualitative and quantitative

Qualitative - Referring to information that is not in numerical form Quantitative - Referring to descriptive data

What are the smallest part of an atom that still retains its properties? An ionic compound? A convalent compound?

particle, formula unit, molecule

Define catalyst.

something that speeds up a reaction without being consumed

What is the law of definite proportions

states that a given chemical compound always contains its component elements in a fixed ratio (by mass and does not depend on its source and method of preparation)

Write the equation for and balance the following: a. Magnesium carbonate + potassium nitrate -> magnesium nitrate + potassium carbonate b. Nickel (II) bromide + barium phosphate -> nickel (II) phosphate + barium bromide c. Sodium + sulfur -> sodium sulfide d. Propane (C₃H₈) + oxygen -> carbon dioxide + water

this too

How many grams of H₂SO₄ are in 3.43 * 10²⁴ particles?

too lazy to do this

Describe Rutherford's gold foil experiment and what it was used to determine.

Experiment was conducted by shooting particles through gold foil onto photo paper. Determined that atoms mostly consist of empty space, with the majority of the mass in the center of the atom—called the nucleus

Find the percent composition of water.

H-11% O-89%

What are the differences between a homogeneous and heterogeneous mixture?

Heterogeneous Mixture - Mixture that has more than one phase (nonuniform) Homogeneous Mixture - Mixture that has only one phase (uniform)

What is the trend for atomic radius? What element has the largest?

Increases down groups and from right to left. Francium has the biggest atomic radius.

What is the trend in electronegativity? Where are the elements with the smallest?

Increases up groups and from right to left. Noble gasses have an electronegativity of zero, due to their valence level being completely filled.

What is ionization energy? What's it's trend?

Ionization energy - The amount of energy it takes to pull an electron from the outside shell of an atom Increases up groups and from left to right.

Define mass and matter

Mass - Amount of matter an object contains Matter - Anything that has mass and takes up space

You measure the length of your desk and get that it is 35.5 cm long. It is actually 41.2 cm long. What is the percent error of your measurement?

((actual - measurement) / actual) * 100 = ((41.2 - 35.5) / 41.2) * 100 = 13.8% error

What are the four evidences that a chemical reaction has taken place?

- Color change - Heat/light produced/absorbed - Solid from a liquid (precipitate) - Gas formed

How did Mendeleev construct his periodic table?

- In order of increasing atomic mass - Groups of elements with similar chemical and physical properties fell in the same vertical column

What are the different atomic models? Which is the most current?

- Thompson "plum pudding" model, no nucleus, protons and electrons scattered within a "bowl" - Rutherford model, electrons circling around a nucleus - Bohr model, introducing electron layers -Quantum mechanical model: most current

Give the location of safety devices such as the vent hood, eyewash, fire blanket, fire extinguisher, etc...

... just know it...

How many electrons can each orbital hold? How many can each sublevel hold?

All orbitals can have a max of 2 electrons s sublevel: 1 orbital = 2 electrons p sublevel: 3 orbital = 6 electrons d sublevel: 5 orbitals = 10 electrons f sublevel: 7 orbitals = 14 electrons

Define coordinate covalent bond.

An atom donates both electrons (ex. CO)

What is a chemical change?

Any change that results in a new chemical substance - Burning - Cooking - Oxidizing

What is an isotope?

Atom of the same element with the same number of protons but different number of neutrons

How many valence electrons are in N, Cl, and Na?

N = 5 valence electrons Cl = 7 valence electrons Na = 1 valence electron

Give examples of elements that would form ionic bonds, nonpolar bonds, and polar bonds.(EN differences)

Na, Cl-ionic H, Br-polar Br, Br-nonpolar S, O-polar

What are the products and reactants?

Reactants are on the left of the arrow in an equation while the products are on the right side of the arrow

What are sigma and pi bonds?

Sigma bond - bond formed between the nuclei of two atoms (top to bottom overlap) Pi bond - formed when you have a double or triple bond (side to side overlap)

What are the characteristics of solids, liquids, and gases?

Solid - Has definite shape and definite volume Liquid - No definite shape, but definite volume Gas - No definite shape and no definite volume

Give the procedure for separating salt and sand.

Step 1: Place the salt and sand mixture into a heat-proof container. Make sure the container is four to five times larger than the sample of salt and sand mixture. Step 2: Add water. To the container of salt and sand, add roughly twice as much water as the mixture. Step 3: Stir the mixture of salt, sand and water to dissolve the salt. Stir until all of the salt has dissolved. If necessary, add small additional amounts of water until all of the salt dissolves. Step 4: Allow the sand to settle. Step 5: Carefully decant the liquid. Slowly tilt the container so that the liquid flows out of the container slowly. Remove as much liquid as possible but do not allow any sand to slip out. Step 6: Evaporate the water from the salt solution to collect the salt. Allow the container to sit until the water evaporates on its own, or heat the solution to drive off the water more quickly.

What information does the atomic number of an element give you?

Tells you how many protons are in an atom of that element, determining its place on the periodic table.

How are elements grouped on the periodic table?

They have identical valance electron configurations and consequently behave in a similar fashion chemically.

What is a covalent compound?

Two nonmetals chemically combined

When is an ionic compound able to conduct electricity and why?

When it is dissolved or molten because that's the only way electrons are free to move

Know safety rules for goggles, chemical safety, lab procedure, fire safety, diluting acids, etc...

You're on something if you think imma type out all that

Write the formula for the following: zinc bromide, dinitrogen monoxide, lead (IV) oxide, copper (I) carbonate.

ZnBr₂, N₂O, PbO₂, Cu₂CO₃

Balance the following equations: a. C₃H₅(NO₃)₃ -> CO₂ + N₂ + H₂O + O₂ b. Na₃PO₄ + ZnO -> Na₂O + Zn₃(PO₄)₂ c. H₂ + O₂ -> H₂O d. NaCl + H₂SO₄ -> Na₂SO₄ + HCl e. Fe + ZnCl₂ -> FeCl₃ + Zn f. C₃H₈ + O₂ -> CO₂ + H₂O

a.) 1->12+6+10+1 b.) 2+3->3+1 c.)2+1->2 d.) 2+1->1+2 e.) 2+3->3+2 f.) 1+5->3+4

Tell the biggest contribution of the following: a. Dalton b. Thomson c. Chadwick d. Schrodinger e. Rutherford f. Goldstein

a.) proposed that all mater was composed of atoms, indivisible and indestructible building blocks. While all atoms were identical, different elements had atoms of differing size and mass b.) discovered the electron by experimenting with a cathode ray tube c.) discovered the neutron in atoms d.) took the Bohr model one step further by using math equations to describe the likelihood of finding an electron in a certain position. This is known as the quantum mechanical model of an atom e.) established the nuclear theory of the atom with his gold-foil experiment by shooting a beam of alpha particles at a sheet of gold foil. A few particles were deflected but some did go through as well. He concluded that a tiny, dense NUCLEUS was causing the deflections f. Discovered protons

What is a quantum, how does it relate to electron theory?

allows us to both simplify and dig deeper into electron configurations

Predict the products and balance the following reactions: e. MgO -> f. Na + ZnCl₂ -> g. C₂H₆ + O₂ -> h. K₃N + BaSO₄ ->

and this too

What are properties of metal explained by the metallic bonding theory?

can occur in different elements to make an alloy malleable ductile good conductors high densities

Define cation and aninon

cation-positively charged ion (CATions are PAWSitive) anion-negatively charged ion

Why is a cation always smaller and an anion is always bigger than the atom formed?

cations are smaller because they lost an electron thus becoming smaller in size, anions gain an electron so increase in size

Give all of Dalton's laws.

♦ All elements are composed of tiny indivisible particles called atoms. ♦ Atoms of the same element are identical. The atoms of any one element are different than those of any other element. ♦ Atoms of different elements can physically mix together or chemically combine in simple, whole number ratios. ♦ Chemical reactions occur when atoms are separated, joined or rearranged, but atoms of one element are never changed into another element as a result of chemical reaction.