A chemical change affects on the molecular level of matter, which makes it irreversible. Combustion is a pretty good exmple. Physical changes are reversible and dont alter the formula. Hope this helped!
Explanation:
The given data is:
The half-life of gentamicin is 1.5 hrs.
The reaction follows first-order kinetics.
The initial concentration of the reactants is 8.4 x 10-5 M.
The concentration of reactant after 8 hrs can be calculated as shown below:
The formula of the half-life of the first-order reaction is:
Where k = rate constant
t1/2=half-life
So, the rate constant k value is:
The expression for the rate constant is :
Substitute the given values and the k value in this formula to get the concentration of the reactant after time 8 hrs is shown below:
Answer: The concentration of reactant remains after 8 hours is 2.09x10^-6M.
Answer:
HBr(aq) + LiOH(aq) → LiBr(aq) + H2O(l)
Explanation:
A neutralization reaction is a process in which an acid, aqeous HBr reacts completely with an appropriate amount of base, aqueous LiOH to produce salt, aqueous LiBr and water, liquid H2O only.
HBr(aq) + LiOH(aq) → LiBr(aq) + H2O(l)
Acid + base → Salt + Water.
During this reaction, the hydrogen ion, H+, from the HBr is neutralized by the hydroxide ion, OH-, from the LiOH to form the water molecule, H2O.
Thus, it is called a neutralization reaction.
Answer:
3 e⁻ transfer has occurred.
Explanation
This is a redox reaction.
- Oxidation (loss of electrons or increase in the oxidation state of entity)
- Reduction (gain of electrons or decrease in the oxidation state of the entity)
- An element undergoes oxidation or reduction in order to achieve a stable configuration. It can be an octet or duplet configuration. An octet configuration is that of outer shell configuration of noble gas.
- [Ne]= (1s²) (2s² 2p⁶)
A combination of both the reactions( Half-reactions) leads to a redox reaction.
Let us look at initial configurations of Al and Cl
[Al]= 1s² 2s² 2p⁶ 3s² 3p¹
[Cl]= 1s² 2s² 2p⁶ 3s² 3p⁵
Hence, Al can lose 3 electrons to achieve octet config.
and, Cl can gain 1e to achieve nearest noble gas config. [Ar]
This reaction can be rewritten, by clearly mentioning the oxidation states of all the entities involved.
Al⁰ + Cl⁰ → (Al⁺³)(Cl⁻)₃
Here, Aluminum is undergoing an oxidation(i.e loss of electrons) from: 0→(+3)
Chlorine undergoes a reduction half reaction (i.e gain of electrons) from: 0→(-1). There are 3 such chlorine atoms, hence 3 e⁻ transfer has occurred.
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