Chem Unit 0

H3P

H3P

Hydrogen phosphide

What is the percent nitrogen (by mass) in ammonium carbonate, (NH4)2CO3?

29.16%

Which one of the following elements forms ions with two different valences?

iron(+3, +2)

Calculate Avg. Atomic Mass

1. Take its percent abundance and turn it into a decimal

2. Then take the percent that is now a decimal and multiple it with its mass in amu

3. Repeat the same steps (1 and 2) for the other isotope

4. Then add both isotopes together

   Ex: .40 x 24.02 amu= 9.608

   .60 x 26.10 amu= 15.66

   15.66 amu + 9.608 amu= 25.268 amu

What is the formula of the ionic compound formed between Mg and Br?

MgBr2

Matter

anything that takes up space and has mass

Matter is classified as

solid, liquid, gas

Matter Composition

elements, componds, mixtures

Pure Substance

made up of only one component

Examples of elements

Carbon (C), Helium (He), Oxygen (O), Nickel(Ni)

Examples of compounds

sodium chloride, glucose, calcium carbonate, water

Mixture

Made up of two or more components

Hetergeneous

Can see the parts, dissimlar (oil and water); its compostion can be either different or similar to each other

Homogeneous

All portion are uniform, similar in nature; same composition and properties( salt water)

Decanting

Pouring off liquid from a precipitate- shows insolubility

Distillation

Seperates homogeneous mixtures of a liquid and solid- are poured through filter paper and funnel

Gravity Filtration

A hetergeneous mixture of a liquid and solid are poured through filter paper and funnel

Vacuum filtration

A vacuum is set up with a sink appratus to aid the filtration process

Physical property(only state and apperance change)

Only apperance and state change, still the same compostion and substance. Ex: Boiling and cutting, color of a substance, melting and density, alcohol evaporating

Chemical property(alters the composition of matter)

Alters the composition of the matter. Ex: New substance, rusting nails, burning magnesium, bubbles forming on metal when dropped in acid, when white phosporous is exposed to air it will burn spontaneously

Energy

The capacity to do work(applying a force over a given difference)

Kinetic energy

The motion of an object

Potential energy

The position of an object, energy stored by an object

Thermal=kinetic

The temperature of an object

Law of Conservation of Energy

Energy cannot be created or destroyed

Temp conversion

C= (F-32)/1.8, K=C + 273.15

Sig figs rules

1. Non-zero digits are always significant. 2. Any zeros between two significant digits are significant. 3. A final zero or trailing zeros in the decimal portion ONLY are significant. 73.00( 4 sig figs, everything after a decimal with a digits in front are significant) 7300(2 sig figs), no decimal , so the trailing zeros don't count

Sig Figs Rules for Multiplication and Division

Answer should have fewest sig figs: 2.389 x 2.5= 5.1

The 2.5 has 2 sig figs, so should the answer

Sig Figs Rules for Addition and Subtraction

Round to the number with the least sig figs but round based on its last placement. 2.54, you would round the number to the hundrendth place. Ex: 2.456 x 2.54= 6.39(since 2.54 ends at a hundredth, so will the 6.39)

Precision(refers to reproductivity of a laboratory measurment)

A measure of how close a series of measurements are to one another

Accuracy

How close the measure is to the actual value

Ex: The bulls eyes on the practice test was neither accurate nor precise becasue the measurements were not close to each other and the points were not close to the bulls eye

Wafting

smelling a chemical substance

When a pure solid substance was heated, a student obtained another solid and a gas, each of which was a pure substance. From this information which of the following statements is ALWAYS a correct conclusion?

The orginal solid is not an element, otherwise only one physical change would have occured

The prefix mili stands for(0.001)

10^-3

Chromatography

Seperates the components in a mixture

Percent Error Formula

Estimated number- Actual number/Actual number x 100

Law of Conservation of mass

Matter cannot be created nor destroyed

Law of definite Proportions

All samples of a compound have the same proportions of the component elements

Law of Multiple Proportions

When two elements form two different coumpounds, the ratio of their masses can be express as small whole numbers

Dalton Atomic theory

1. Each element is composed of tiny, indestructible particles called atoms.

2. All atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements.

3. Atoms combine in simple, whole-number ratios to form compounds.

4. Atoms of one element cannot change into atoms of another element. In a chemical reaction, atoms only change the way that they are bound together with other atoms.

Structure of Atom

Protons and neutrons are inside the nucleus, electrons are outside the nucleus in electron clouds, relative mass of protons and neutrons is , relative mass of electron is 0

Isotopes

atoms with the same number of protons but a different number of neutrons

Natural Abundance

the relative amount of each isotope in a given sample of an element

Average atomic mass

a weighted average of an elements mass based on the masses and abundance of each isotope

Mass Spectroscopy

an analytical technique that measures the natural abundance of isotopes

Cations and Anions

Cations lose electrons(positive charge), Anions gain electrons(negative charge)

Which of the following is a metalloid( the stair case on the periodic table)

As, Si, B, Te, At

Which of the following is a transition metal

Ni, Co, Cu, Zn, Zr

Which of the following is an alkali metal( the first column on the periodic table, except H)

K, Na, Li, Rb, Cs

Which of the following is an lanthanide( the 6th row)

Eu, Au, Hg, Ta, La

Ionic Bonds

Transfer metals

Covalent Bonds

Share metals

Diatomic Molecules(I Have No Bright Or Clever Friends)

H2, N2, O2, F2, Cl2, Br2, and I2.

BrINClHOF

HONClBrIF

I Have No Bright Or Clever Friends

Ate vs Ite( ate is bigger, it is smaller)

If there are two ions in the series,

the one with more oxygen atoms has the ending -ate, and

the one with fewer has the ending -ite.

Oxyanions(per means more than, hypo means less than)

If there are more than two ions in the series then the prefixes hypo-, meaning less than, and per-, meaning more than, are used.

Organic compounds

Contain, hydrogen, carbon and sometimes oxygen or nitrogen

Burning organic compounds

For mass analysis, can be used to determine the original emperical formula

Naming compounds

Ionic Compounds: just give the names of the two ions involved

• Transition Metals use Roman Numerals to show the charge

• -ide ending just means the element

• Molecular (Covalent):  use the number prefixes

• Acids:  H and an anion

  • Anion ending determines acid name

• Hydrates:  Ionic compound name followed by prefix showing how many water molecules

Certain properties are characterstic of meals. Which property means that you can pound the substance into a foil

Malleability

Which element has the highest melting point

W

Cathode rays start at the

negative electrode

cathonde rays are

positive ions

Which wil be delfected the least in a mass spectrometer

+1, 4 amu( large mass small charge)

In milikian oil drop tpe experiment, the charge on four oil drops was found to be(divide by smallest factor)

1- 3.33 coulombs

2.67- 8.88

2- 6.66

3.33- 11.10

What is the charge on the elctron according to this experiment

1.11 coulomb

3.33 divided by 3= 1.11

What scattered particle the best evidence for nuclear attom(balance)

a

Which of the following is an isotope of the element with 20 protons and 22 neutrons-42

Calcium 40 because 42-20= 22, and 18 neutrons

Match the answers to the key

Gamma is a high energy form of light

Beta is a high speed electron, associated with neutron changing into proton

alpha used by ernest rutherford as “probe”

Gamma is the most penetratng of the “bequerel rays”

Use the following key to math individuals

John Dalton’s atom has been called “billiard ball” model

J.J Thomas has studied matter in cathode ray tubes, and has added to the atomic theory the idea that atomas had positive and negative parts

Democritus has a philosophical idea included the term “atomos”

Which elements did mendeleev leave spaces for

Ga, Ge, Sc

The imaginary elemnent X has the following natural abundances and isotopic masses. What is the atomic weight of X

25.3 amu

Calculate the % abundances of two isotopes of cooper

62.9298x + 64.9278(1-x)= 64.546amu

0.3818 = 1.998x

19.11% cu-63

80.89% cu-65

What is the formula of the ionic compound formed between Ca and P?

Ca3P2

What is the name of the SO32– ion?

sulfite

What is the correct formula and charge for the chromate ion?

CrO42

The correct name for CCl4 is

carbon tetrachloride

The correct formula for hydrogen telluride is

H2Te

The correct name for S2Cl2 is

disulfur dichloride

The correct name for NO2 is

nitrogen dioxide

The molar mass of (NH4)2S is closest to

68 g/mol

How many atoms are in 12 molecules of glucose, C6H12O6?

288

Calculate the number of atoms in 4.0 x 10-5 g of aluminum.

8.9 x 10^17

What is the mass of one molecule of octane, C8H18?

1.89 x 10-22 g

A compound consists of the following elements by weight percent:

carbon - 40.0%

oxygen - 53.3%

hydrogen - 6.7%

The ratio of carbon : oxygen : hydrogen in the empirical formula is

1:1:2

An organic compound which has the empirical formula CHO has a molar mass of 232.  Its molecular formula is:

C8H8O8

Of the following, the only empirical formula is

HNF2

When CaSO4·y H2O is heated, all of the water is driven off.  If 34.0 g of CaSO4 [molar mass = 136] is formed from 43.0 g of CaSO4·y H2O, what is the value of y?

2

A metal sample weighing 30.9232 grams was added to a graduated cylinder containing 23.26mL of water. The volume of water plus the sample was 24.85mL. Which setup will result in the densit of this metal.

30.9232/24.85-23.26

Mercury has a density of 13.58g/mol. What is the volume of mercury when its poured out to obtain 0.5000 g of mercury

0.03682

Kelvin to celsius to fahrenheit

K= C +273.15

F= (c-32)/1.8

Chromate

CrO4^2-

Chromite

FeCr2O4

Sulfate

SO4^2-

Sulfite

SO3^2-

Nitrite

NO2⁻

Nitrate

No3^-

What is the atomic number of potassium

19

how many electrongs are in the potasium nucleus

0

Signs of Chemical Change

1. Permanent color change

2. Gas release(bubbles/odo)

3. Precipitate produced

4. Light given off

5. Heat absorbed or released

Pb3N2

Lead(II) nitride