18 Balance this equation using the smallest possible integers, s INO, .Ilzso. \"

Question

18 Balance this equation using the smallest possible integers, s INO, .Ilzso. "Non What is the coefficient of water. A) I B) 4 C) 6 D) 10 19 Asample of chemical xisfound to eomain sograms of oxygen, 10 grams of carbon, and 20 grams of nitrogen, The law of definite proportion would predict that a 71 gram sample of chem X should contain how many grams ofcarbon? A) 15 grams B) 20 grams c) 10, grams D) 5.0 grams EO 7.1 grams 20 Which of the following ions forms the fewest insoluble salts? B) No C) Mg D) AP" E) ohl l. In which of the following does iodine have the lowest oxidation state? A) B) NH41 c) Lilo, D) E) LO Which of the following atoms, isotopes or ions contains 23 protons, 18 electrons and 27 n A) "Cos" D) seKr B) Krs. C) Select the spectator ions for the following reaction in aqueous solution, AgNO, Lil iNO, Li (aq) (aq) Li (aq) NO, (aq) Ag (aq), NO, (aq) Ag (aq), (aq), Li (aq), NO, (aq) Ag (aq), l (aq)

Explanation / Answer

18.

The given chemical equation which is to be balanced is,

S + HNO3 = H2SO4 + NO2 + H2O

The chemical equation after balancing is,

S + 6HNO3 ---------------> H2SO4 + 6NO2 + 2H2O

In this balanced equation, the coefficient of water is 2.

So, option E is correct.

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19.

Law of definite proportion states that a chemical compound always contains exactly the same proportion of elements by mass. This is also called Law of constant composition.

Given, a chemical compound X contains, 5.0 g Oxygen, 10.0 g Carbon and 20.0 g Nitrogen.

So, it means that 10.0 g of Carbon is present in 35.0 g of total chemical X.

So, the percentage proportion of carbon is (10.0 / 35.0) x 100 = 28.5 %

And, we were asked to find the amount in 71 g of sample of Chemical X.

It means that, 28.5% of 71 g sample of chemical X is Carbon.

Amount of Carbon = 71 x (28.5 / 100) = 20.2 =20 g

So, option B is correct.

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20.

From the solubility rules, we know that, maximum of all Nitrates are soluble.

That means, it has fewest insoluble salts.

So, option B is correct.

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21.

Iodine in option A (I2) is zero, as it is in Molecular form.

In NH4I, N has -3, H has +1, and I has -1 oxidation state.

In LiIO3, Li has +1, I has +5 , O has -2 oxidation states.

In IO2, I has +4, and O has -2 oxidation states.

In I2O, I has+1 and O has -2 oxidation states.

So, only NH4I has I with -1 oxidation state, which is less among the given.

So, option B is correct.

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22.

Given that the isotope has 23 protons.

It means that, the atomic number of the element is 23.

The element with atomic number 23 is Vanadium [V].

So, option C or E is correct.

And it was given that there are 18 electrons.

So, for option C, 50 V 5-, electrons = Protons - (charge)

Electrons = 23-(-5) = 28 (Incorrect)

For option E, 50 V 5+, electrons = Protons - (charge)

Electrons = 23-(+5) = 18 (Correct)

Let us check for neutrons finally.

Neutrons = Mass number - Protons

= 50-23 = 27

Option E satisfies all the criteria.

So, option E is correct.

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23.

Given equation is AgNO3 + LiI --------------> AgI + LiNO3

AgI is a precipitate.

So, the reaction is AgNO3(aq) + LiI(aq) --------------> AgI(s) + LiNO3(aq)

So, the spectator ions are Li+ and NO3-

So,option B is correct.

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