Respuesta :
Answer: 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 [tex]H^+[/tex] 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:
[tex][H_3O^+]=[OH^-][/tex]
Explanation:
The pH of water is 7.And Ionic product of water is [tex]1\times 10^{-14}[/tex]
[tex]pH=-\log[H_3O^+]=7[/tex]
[tex][H_3O^+]=1\times 10^{-7}[/tex]
[tex]K_w=1\times 10^{-14}=[H_3O^+][OH^-][/tex]
[tex][H_3O^+]=[OH^-][/tex]
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.
[tex]2K+Cl_2\rightarrow 2KCl[/tex]
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[tex]MgCl_2[/tex]
Explanation:
[tex]Mg(OH)_2+2HCl\rightarrow MgCL_2+2H_2O[/tex]
The salt formed is magnesium chloride[tex]MgCl_2[/tex] along with water.
Answer:
Q1 - Only nuclear reactions change the identity of an element, since they work with the element nucleus which is the atom's part that involves the number of protons in it. The protons define what element we are using in the reaction.
Q2- Rate of condensation = rate of evaporation, since water is in liquid form and the two possible transformations that can happen without changing the flask's temperature are condensation and evaporation. There is no solid form involved to cause precipitation and we don't calculate the moles based on the state the molecules are presented like liquid and vapor.
Q3- Solid phase of matter has a definite shape and volume, since the molecules are arranged in a specific way, close to each other and without much movement possibilities.
Q4- Exothermic, since the reaction involves heat liberation, which characterizes exothermic reactions.
Q5 - Acid feel slippery is not a true consideration when talking about acids' properties. This property would be true to bases, which explains the soapy feeling when it degrades fats into soap.
Q6- It increases the average of kinetic energy and number of collisions per minute, because it gives kinetic energy to the molecules involved in the process, making them move faster and collide more to each other.
Q7- [H3O+]=[OH-] , since those are the ions in water molecules. When combined, they form H2O, the pure water form.
Q8- Gamma rays can penetrate your body the deepest, since they are very energized and short-wavenlenghted. These properties make it easier for them to penetrate into your body.
Q9 - K, because it lost one electron due to the ionic bond that is being formed in the product KCl.
Q10- The products are at a lower energy level than the reactants, since energy is lost during the reaction through heat liberation (exothermic reactions liberate heat to the surroundings).
Q11 - MgCl2, since a salt is composed by two inorganic elements.
