Explanation:
Question 18: Double displacement reaction
Reaction:
2LiBr + Pb(NO₃)₂ → PbBr₂ + 2LiNO₃
This reaction is called a double displacement reaction.
It occurs between ionic compounds that exchange their ions to form completely new products.
The reaction involves an actual exchange of partners to form new compounds:
AB + CD → AD + CB
One of the following serves as a driving force for double replacement reactions:
formation of a precipitate which is an insoluble compound
formation of water or any other non-ionizing compound.
Productions of a gaseous product
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Formation of precipitate brainly.com/question/8896163
Question 19: Single displacement reaction
Fe + 2HCl → FeCl₂ + H₂
The above reaction is a single displacement reaction. It can also be called a single replacement reaction.
In this reaction, a substance is replacing another:
A + BC → AC + B
The replacement of metallic ions by a metal higher in the activity series than the metal in solution falls into this category.
The driving force of this reaction stems from the displacement of a metal high up in the activity series compared to the lower one .
In the series, iron is higher and more reactive. It will displace hydrogen from HCl in solution.
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Double displacement brainly.com/question/8896163
Question 20: Combination or synthesis
CaO + H₂O → Ca(OH)₂
This reaction is combination or synthesis .
It involves the formation of a single product from two or more reactants.
The formation of a product by the union of elements and molecules falls into this category.
The large and negative heat of formation of the product is the driving force for the reaction.
Learn more:
Synthesis brainly.com/question/4216541
Question 21: Decomposition or cracking
NiCl₂ → Ni + Cl₂
This is decomposition or cracking reaction.
In this reaction type, two or more products forms from a single reactant.
A compound breaking down into other compounds simply falls into this category.
The instability of the compound and the positive heat of formation drives this reaction.
Compounds can decompose naturally on their own.
Under pressure and temperature, they can also decompose
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Decomposition
Question 22-24
Chemical species:
Hydrogen Chloride HCl
Sodium sulfide Na₂S
Hydrogen sulfide H₂S
Sodium chloride NaCl
22. HCl and Na₂S
23. H₂S and NaCl
unbalanced equation:
HCl + Na₂S → H₂S + NaCl
A chemical reaction is usually represented by a chemical equation.
A chemical equation is made up of reacting species that gives specific products.
Different equations depicts different forms of chemical reaction
The left hand side is made up of the reacting species called reactants.
The right hand is the product side.
24. Balanced equation:
aHCl + bNa₂S → cH₂S + dNaCl
first examine the equation to see if it is balanced.
Here i will be using a mathematical approach to balance the equation:
a,b,c and d are the coefficients that will balance the reaction.
Conservation of H: a = 2c
Cl: a = d
Na: 2b = d
S: b = c
let us make a = 1;
c=
b =
d = 1
Multiply through to obtain whole number ratios
a = 2
c= 1
b = 1
d = 2
2HCl + Na₂S → H₂S + 2NaCl
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Chemical equation brainly.com/question/2924195
Question 25: Alpha particles < Beta particles < Gamma rays
Nuclear radiation are attendants emissions that accompanies radioactive decay releasing small particles and electromagnetic ionizing radiations with considerable amount of energy.
- There are three major types of ionizing radiations which are alpha particles, beta particles and gamma rays.
- Gamma rays are electromagnetic radiations whereas alpha and beta particles are very tiny particles.
- All the radiation types cause ionization of gas molecules as they traverse through any medium this is why they are called ionizing radiations.
- Gamma rays are most ionizing of the radiations due to their high energetic properties.
Learn more:
Irradiation brainly.com/question/10726711
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