Gen Chem 1 final

Cathode rays are deflected away from a negatively charged plate bc ____

a. they are positively charged particles

b. they are not particles

c. they are neutral particles

d. they are emitted by all matter

e. they are negatively charged particles

e. they are negatively charged particles

in which of the following numbers are all of the zeros significant

a. 100.090090

b.0.0010

c. 0.0001

d.0.1

e.0.143290

a. 100.090090

which statement below correctly describes the response of alpha, beta, and gamma radiation to an electric field

a. alpha and beta are deflected in opposite directions, while gamma shows no response

b. only alpha is deflected, while beta and gamma show no response

c. both alpha and gamma are deflected in the same direction, while beta shows no response

d. both alpha and beta are deflected in the same direction while gamma shoes no response

e. both beta and gamma are deflected in the same direction, while alpha shows no response

a. alpha and beta are deflected in opposite directions, while gamma shows no response.

• Alpha particles (α\alpha) are positively charged, so they are attracted toward the negative plate in an electric field.

• Beta particles (β\beta) are negatively charged, so they are attracted toward the positive plate—meaning they deflect in the opposite direction to alpha particles.

• Gamma rays (γ\gamma) have no charge, so they are not affected by an electric field and travel straight through.

law of multiple proportions

The Law of Multiple Proportions states that when two elements combine to form more than one compound, the ratios of the masses of one element that combine with a fixed mass of the other element are simple whole numbers.

Example: Oxygen and Carbon Compounds

Let's look at carbon and oxygen, which form two different compounds: carbon monoxide (CO) and carbon dioxide (CO₂).

• In CO, the ratio of oxygen to carbon (by mass) is 1.33:1.

• In CO₂, the ratio of oxygen to carbon (by mass) is 2.66:1.

• The ratio of oxygen in CO₂ to CO is 2:1 (a simple whole number).

round 0.007222 to three sig figs

0.00722

isotopes of the same element

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons in their nuclei. This means they have the same atomic number but different atomic masses.

ex. 14 over 6 and 12 over 6

smallest and lightest subatomic particle

electron

gold foil experiment led to

discovery of the atomic nucleus

precision refers to

how clase a measured number is to other measured numbers

formula weight of silver chromate (Ag2CrO4) is ___ amu

331.73

which of the following has the same number sig figs 1.00310

a. 5.119

b. 199.791

c. 8.66

d. 11.762

e. 1 × 10^6

b. 199.791

all atoms of a given element have the same

number of protons

combustion reaction is

Fuel+O2→CO2+H2O+heat

round 3456.5 to 2 sig figs

3500

combo of sand, salt and water is an ex of

heterogenous mixture

for which of the following can the composition vary

a. element

b. heterogenous mixture

c. homogenous mixture

d. both homogenous and heterogenous mixture

e. solid substance

(d) both homogeneous and heterogeneous mixtures.

Here's why:

• Elements (a) have a fixed composition—each atom of an element has the same number of protons.

• Heterogeneous mixtures (b) have varying compositions because their components are not uniformly distributed (like a salad or trail mix).

• Homogeneous mixtures (c) can also have varying compositions because you can mix different amounts of components (like saltwater or air).

• Solid substances (e) can be either elements or compounds, meaning their composition may be fixed.

the most common isotope of gold, 197^Au has ___protons, ___neutrons, ____electrons

79 protons and electrons

118 neutrons

what are intensive properties

Intensive properties are characteristics of a substance that do not depend on the amount of matter present. No matter how much or how little of the substance you have, these properties remain unchanged.

Examples of Intensive Properties:

• Density – A gold bar and a gold coin have the same density.

• Boiling Point – Water always boils at 100°C at standard pressure, whether it's a cup or a lake.

• Melting Point – Ice melts at 0°C, regardless of the size.

• Color – A small piece of copper is still reddish-brown, just like a large sheet of copper.

• Conductivity – Silver is a great conductor whether it's a tiny wire or a large block.

Milikan oil drop experiment lead to

the charge of electron

combination rxn

A+B→ C

law of constant composition definition

states that a pure compound always contains the same elements in the same proportion by mass, no matter where or how it’s made.

decomposition rxn

C→ A+B

Postulates of Dalton’s Atomic theory

1. Everything is made of tiny particles called atoms. You can’t see them, but they’re the building blocks of everything.

2. Atoms of the same element are exactly alike. (All oxygen atoms are the same, all gold atoms are the same, etc.)

3. Atoms of different elements are different. (Oxygen atoms are different from gold atoms.)

4. Atoms combine in fixed ways to make compounds. (Water is always H₂O, never H₂O₂ by accident!)

5. Atoms don’t disappear or change into different atoms during chemical reactions. They just rearrange to form new substances.

an element cannont

a. be part of a homogenous mixture

b. be part of a heterogenous mixture

c. interact with other elements to form compounds

d. be separated into other substances

e. be a pure substance

d. be separated into other substances

the formula weight of a substance is

a. identical to the molar mass

b. the same as the percent by mass weight

c. the weight of a sample of the substance

d. determined by combustion analysis

is the sum of the atomic weights of all atoms in a chemical formula. It is numerically equal to molar mass, which is measured in grams per mole (g/mol).

what is a strong base

is a substance that completely dissociates in water to release hydroxide ions (OH⁻). This means all of its molecules break apart, making it highly effective at neutralizing acids.

what are the respective concentrations of (M) of Mg+2 and Cl- afforded by dissolving 0.325 mol MgCl2 in water and diluting it to 250mL

1.30 and 2.60

avagadros number

6.022×10²3

how many SO2 molecules are there in 0.180 mol of SO2

1.08 ×10²3

what is an electrolyte

dissolves in water (or another solvent) to produce a solution that conducts electricity. This happens because the substance breaks apart into ions, which carry electrical charge.

What volume (mL) of a concentrated solution of sodium hydroxide (6.00M) must be diluted to 200mL to make a 0.880M solution of sodium hydroxide

M1V1=M2V2

29.3

oxidation is and reduction is

the loss of electrons

the gain of electrons

which of the following is insoluble in water at 25 degrees Celsius

a. Na2S

b. (NH4)2CO3

c. Mg3(PO4)2

d. Ca(OH)2

e. Ba(C2H3O2)2

• Group 1 (Na, K, Li) compounds, ammonium (NH₄⁺), nitrates (NO₃⁻), and acetates (C₂H₃O₂⁻) are generally soluble.

• Phosphates (PO₄³⁻) are mostly insoluble, except for Group 1 and ammonium salts.

So, Mg₃(PO₄)₂ is the insoluble compound among the options.

a neutralization reaction between an acid and a metal hydroxide produces

water and salt

how many moles of Co2+ are present in 0.200L of a 0.400M solution of CoI2

Moles=Molarity×Volume

0.0800

combining aq solutions of BaI2 and Na2SO4 affords a precipitate of BaSO4, which ions are spectator ions

Na+ and I-

one million argon atoms is ___ mol (rounded to two sig figs) of argon atoms

1.7 × 10^-18

what is the concentration of M of a NaCl solution prepared by dissolving 9.3g of NaCl in sufficient water to give 350 mL of solutotion

0.45

arrange the following gases in order of increasing average molecular speed at 25 degrees C

He, O2, CO2, N2

Since lighter gases move faster, the correct order of increasing molecular speed is:

CO2<O2<N2<He

the internal energy of a system

a. refers only to the energies of the nuclei of the atoms of the component molecules

b. is the sum of the rotational, vibrational and translational energies of all its components

c. is the sum of the potential and kinetic energies of the components

d. is the sum of the kinetic energy of all its components

e. none of the above

c.The internal energy of a system is the sum of the potential and kinetic energies of its components.

Internal energy (UU) includes:

• The kinetic energy of molecules (due to translational, rotational, and vibrational motion).

• The potential energy from intermolecular forces and bond interactions.

the term standard conditions with respect to enthalpy change means

1 atm and 298K

the differenceE of a system that absorbs 12.4J of head and does 4.2J of work on the suroundings is

8.2J

an ideal gas differs from a real gas in that the molecules of an ideal gas

have no attraction for one another

when ___ is constant the enthalpy change of a process equal to the amount of head transferred into or out of our system

pressure

the kinetic molecular theory predicts that pressure rises as the temperature of a gas increases bc___

the gas molecules collide more frequently with the wall

the gas molecules collide more energetically with the wall

the internal energy can be decreased by

transferring heat from the surroundings to the system

doing work on a system

one significant difference between gases and liquids is

a gas expands to fill its container

objects possess energy as

KE and PE

differenceH degrees f is zero for

solids

the molar volume of a gas at stp is ___

22.4L

Hess Law

the total enthalpy change of a reaction is the same, no matter how many steps it takes.

(the sum of the enthalpy changes)

Charles Law

the volume of a gas increases as its temperature increases, as long as pressure is constant.

V1T1=V2T2

of the following gases, ____ will have the greatest rate of effusion at a given temp

NH3, Ar, HCl, CH4, HBr

The gas with the lowest molar mass will have the highest rate of effusion. That means CH₄ (Methane) will effuse the fastest, followed closely by NH₃.

what is state function

capitol letter

Boyle’s Law

states that if temperature is constant, the pressure and volume of a gas are inversely related—meaning, when one increases, the other decreases.

P1V1=P2V2

a real gas will behave most like an ideal gas under conditions of

high temp and low pressure

a ___ differenceH corresponds to an ___ process

negative, and exothermic

positive and endothermic

STP in the context of gases refers to

273.15K and 1 atm