The boiling point of Sodium chloride(aq) is higher and the freezing point of Sodium chloride(aq) is lower.
The boiling point is the temperature at which the pressure exerted by the surroundings upon a liquid is equal to the pressure exerted by the vapour of the liquid.
Usually, in this context, you would be referring to the boiling and freezing point of a Sodium chloride solution compared to pure H2O.
The boiling point of pure water is 100 degrees Celcius (212 Fahrenheit), and the freezing/melting point is below 0 degrees Celcius (32 Fahrenheit). For a solution, the boiling point is raised and the melting point is lowered.
This means that water will stay liquid for an increased range of temperature. Depending on the amount of Sodium chloride solute in the water, the boiling and melting points may change a few degrees.
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Answer is: D. substitution.
Substitution reaction or single displacement reaction is a chemical reaction in which one functional group in a chemical compound is replaced by another functional group.
Balanced chemical reaction: CH₃Br(aq) + OH⁻(aq) → CH₃OH(aq) + Br⁻(aq).
In this balanced chemical reaction hydroxy group OH⁻ replaced one atom of bromine (Br⁻) in methyl bromide (CH₃Br).
Answer : The correct option is, (D) Substitution reaction.
Explanation :
Addition reaction : It is a type of reaction in which a molecule combined with the another molecule to give a new larger molecule.
The general representation of this reaction is,
Condensation reaction : It is a type of reaction in which two molecules combine to form a larger molecule and also producing a smaller molecule such as water.
Elimination reaction : It is a type of reaction in which the loss of elements from the starting material to form a double bond in the product.
The general representation of this reaction is,
Substitution reaction : It is a type of reaction in which one functional group is replaced by the another functional group.
The general representation of this reaction is,
(B and C are the two different functional groups)
In the given reaction, Br (functional group) is replaced by the hydroxide ion (functional group). So, this reaction is a substitution reaction.
Hence, the given reaction is a substitution reaction.
A.
Only the Fe is unbalanced.
B.
Only the O is unbalanced
C.
Fe and O are both unbalanced.
D.
C and O are both unbalanced
These are two questions and two answers.
Question 1: Law of Conservation of Mass
Answer: option B. The total mass remains the same during a chemical reaction.
Explanation:
The law of conservation of mass is a universal law. It states that mass is mass is neither created or destroyed, but is is conserved.
In chemical reactions, that means that, always, the total mass of the reactants equals the total mass of the products or, as the option B. states, during a chemical reaction the total mass remains the same.
Since, in chemical reactions, the atoms are not modified (the atoms just bond in different form or with different atoms), that implies that total number of each kind of atoms in the reactants equals the total number of the same kind of atoms in the products.
That is the basis for balancing the chemical equations and for the stoicheometric calculations.
Question 2 . Which element(s) are not balanced in this equation?
Answer: option A. Only the Fe is unbalanced.
Explanation:
1) Given equation: Fe₂O₃ + 3 CO → Fe + 3 CO₂
2) Count the number of atoms of each kind on each side of the equation
i) Fe
reactant side: 2
product side: 1
Therefore, Fe is not balanced
ii) O
reactant side: 3 + 3 = 6
Product side: 3 × 2 = 6
Therefore, it is balanced
iii) C
reactant side: 3
product side: 3
Therefore, C is balanced.
3) Conclusion: Only the Fe is unbalanced.
For #1, the answer is B. The total mass remains the same during a chemical reaction.
For #2, given Fe2O3 + 3CO -> Fe + 3CO2
Fe is unbalanced, and O is also unbalanced
Therefore, Option C: Fe and O are both unbalanced, is true.
Mg(s) + N2(g) --> Mg3N2(s)
51 Balance the equation in your answer booklet for the reaction between magnesium and nitrogen, using the smallest whole-number coefficients. [1]
52 In the ground state, which noble gas has atoms with the same electron configuration as a magnesium ion? [1]
53 Explain, in terms of electrons, why an atom of the metal in this reaction forms an ion that has a smaller radius than its atom. [1]
51)
Mg(s) + N₂(g) --> Mg₃N₂(s)
There is one Mg atom on the reactant side and three Mg atoms on the product side. So to balance the number of Mg on both side of the equation a coefficient 3 is placed before Mg on the reactant side. The number of N atoms are two on both side of the reaction. Therefore the balanced chemical equation is,
2Mg(s) + N₂(g) --> Mg₃N₂(s)
52)
The electron configuration of Mg is 1s²2s²2p⁶3s² or [Ne]3s²
The electron configuration of Mg²⁺ is 1s²2s²2p⁶ or [Ne]
The electron configuration of Ne is 1s²2s²2p⁶
Ne he same electron configuration as a Mg²⁺ ion.
53)
Mg has its valence electron in the 3s shell, but Mg²⁺ has no electron in the 3s shell, the valence electron in Mg²⁺is in the 2p orbital. The size of the 2 shell is smaller than the 3 shell. Hence, Mg²⁺ is smaller than Mg.
The balanced equation for the reaction between magnesium and nitrogen is 3Mg(s) + N2(g) -> Mg3N2(s). Neon has atoms with the same electron configuration as a magnesium ion. When an atom of a metal forms an ion, it loses electrons and has a smaller radius.
51. The balanced equation for the reaction between magnesium and nitrogen is:
3Mg(s) + N2(g) → Mg3N2(s)
52. The magnesium ion has the same electron configuration as a neon atom because both have the electron configuration of 2,8. Therefore, neon is the noble gas with atoms having the same electron configuration as a magnesium ion.
53. When an atom of a metal forms an ion, it loses one or more electrons to achieve a stable electron configuration. This results in a decrease in the size of the ion compared to the neutral atom. The loss of electrons reduces the repulsion between the remaining electrons, causing the ion to have a smaller radius.
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