Check my semester exam ! i have a flight to must submit !

question 1 (multiple choice worth 2 points)

[07.06]what is the major difference between nuclear and chemical reactions?

only chemical reactions release energy.

only chemical reactions release gamma rays.

only nuclear reactions involve the exchange of electrons.

i picked: only nuclear reactions change the identity of an element.

question 2 (multiple choice worth 2 points)

[07.03]when water is added to an erlenmeyer flask and then sealed, phase equilibrium occurs. which answer explains the resulting dynamic equilibrium?

rate of evaporation = rate of precipitation

i picked: rate of condensation = rate of evaporation

moles of vapor = moles of liquid

moles of vapor = moles of solid

question 3 (multiple choice worth 2 points)

[05.01]which phase of matter is made up of particles that are packed closely together, with both a definite shape and a definite volume?

gas

liquid

plasma

i picked: solid

question 4 (multiple choice worth 2 points)

[06.02]when sulfuric acid is poured on sugar the volume of sugar expands and the sugar turns black and becomes very hot. which of the following best describes this reaction?

endothermic

i picked: exothermic

decomposition

synthesis

question 5 (multiple choice worth 2 points)

[07.01]which of the following is not true of acids?

acids are corrosive.

i picked: acids feel slippery.

acids have a sour taste.

acids have more hydronium ions than hydroxide ions.

question 6 (multiple choice worth 2 points)

[06.04]according to the collision theory, what is the best explanation for why a higher temperature makes a reaction go faster?

there are fewer collisions per minute.

it increases the distance between the particles.

it decreases the average kinetic energy of the particles.

i picked: it increases the average kinetic energy and number of collisions per minute.

question 7 (multiple choice worth 2 points)

[07.02]which of the following represents pure water?

[h3o+] > [oh-]

[h3o+] < [oh-]

i picked: [h3o+] = [oh-]

[h3o+] [oh-] = 14

question 8 (multiple choice worth 2 points)

[07.06]which of the following types of radiation can penetrate the most deeply into your body?

alpha rays

beta rays

i picked: gamma rays

proton rays

question 9 (multiple choice worth 2 points)

[07.05]in the chemical reaction shown below, which element was oxidized?

2k + cl2 yields 2kcl

i picked: k, because it lost one electron

k, because it gained one electron

cl, because it lost one electron

cl, because it gained one electron

question 10 (multiple choice worth 2 points)

[06.02]on an exothermic potential energy diagram, what is true for the products?

the products are at the same energy level as the reactants.

i picked: the products are at a lower energy level than the reactants.

the products are at a higher energy level than the reactants.

the products do not have energy.

question 11 (multiple choice worth 2 points)

[07.02]what is the salt formed in the following neutralization reaction?
mg(oh)2 + hcl yields h2o + mgcl2

mg(oh)2

hcl

h2o

i picked: mgcl2

The correct answer is:

Only nuclear reactions change the identity of an element.

Explanation

Chemical Reaction: Rearrangement of atoms in a molecule or ions. During a chemical reaction exchange of electrons takes place.

Nuclear reaction  :In these type reaction nucleus of an atom is involved.They classified into two types that is fusion (fusing of two nuclei) and fission (breaking of one bigger nucleus into smaller nuclei).

Answer 2 :The correct answer is option:

Rate of condensation = rate of evaporation

Explanation:

When water is added to an Erlenmeyer flask and sealed. Equilibrium between the condensation and evaporation will be attained that is amount of water getting evaporated is equal to the amount of the water getting condensed.

Rate of condensation = Rate of condensation.

Answer 3: The correct answer is option solid.

Explanation:

Phases of matter :

Solid:The molecules in this state are closely packed together. Due to very close packing of solids have definite shape and definite volume.

Liquids: The molecules in this state of matter are loosely packed which accounts for their indefinite shape and definite volume.

Gas :The molecules in this state of matter are far apart which accounts fro their indefinite shape.

Plasma is the state of matter in which charged particles are present in the gaseous state.

Answer 4:The correct answer is Exothermic reaction.

Explanation:

An exothermic reaction are those reaction which releases heat into their surroundings. the heat released increase the temperature of surrounding.

So,when sulfuric acid is poured on to the sugar it turned into black mass with release of heat energy due to which it became hot.Hence exothermic reaction.

Answer 5:The false statement for the acid is : Acids feel slippery.

Explanation:

Acid are those compounds which   ion is their aqueous solution.They taste sour and corrosive in nature.

Answer 6:

Explanation:

According to Collision theory, at higher temperature kinetic energy of particles increases due to which rate of collision between the reactant molecule increases result in increase in rate of a chemical reaction.Hence, at higher temperature reaction go faster.

Answer 7: The correct answer is:

Explanation:

The pH of water is 7.And Ionic product of water is

Answer 8: The correct answer is gamma rays.

Explanation:

Due to very high energy of the gamma radiations they can penetrate deeply into our body.

Answer 9:K, because it lost one electron

Explanation:

Oxidation : Loss of electron is termed as oxidation.

Reduction : Addition of electrons is termed as Reduction.

Potassium metal is getting oxidized into potassium ion by loosing an electron to chlorine atom.

Answer 10:The correct answer is :

The products are at a lower energy level than the reactants.

Explanation:

In an exothermic potential energy diagram, product are at lower energy level than reactant this because excessive energy produced during reaction is released as heat energy into the surroundings .And this the reason for the lower energy level of the products than reactants.

Answer 11: The salt formed is magnesium chloride

Explanation:

The salt formed is magnesium chloride along with water.

its mg hope this

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