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3 years ago

Select the correct answer.

Chemistry

1 answer:

muminat3 years ago

7 0

Answer:- B. 4.65 g.

Solution:- The given balanced equation is:

$2AgNO_3(aq)+Na_2S(aq)\rightarrow Ag_2S(s)+2NaNO_3(aq)$

It asks to calculate the mass of silver sulfide formed by when 0.0150 liters of 2.50 M of silver nitrate are used.

Moles of silver nitrate are calculated on multiplying it's liters by its molarity and then on multiplying by mol ratio, the moles of silver sulfide are calculated. These moles are multiplied by the molar mass to convert to the grams.

Molar mass of $Ag_2S$ = 2(107.87)+32.06 = 247.8 g per mol

The dimensional set up for the complete problem is:

$0.0150L(\frac{2.50molAgNO_3}{1L})(\frac{1molAg_2S}{2molAgNO_3})(\frac{247.8gAg_2S}{1molAg_2S})$

= $4.65gAg_2S$

So, the correct choice is B. 4.65 g.

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Answer:

a. +6;

b. +5;

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Explanation:

Start with elements with well-known oxidation states.

The oxidation state on oxygen O in compounds is mostly -2. Common exceptions include:

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The oxidation state on group 1 metals (Li, Na, K, etc.) in compounds is mostly +1.

The oxidation state on group 2 metals (Be, Mg, Ca, etc.) in compounds is mostly +2.

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The oxidation state on hydrogen H in compounds is mostly +1. The oxidation state on H might be negative when it is bonded to metals.

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Oxidation states:

Ba: +2;
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O: -2.

Let the oxidation state on S be x.

2 + x + 4 × (-2) = 0;

x = 6.

Hence, the oxidation state on S in BaSO₄ is +6.

Oxidation states:

H: +1;
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Let the oxidation state on Cl be x.

<em>Refer to the equation in BaSO₄ as an example. Try setting up the equation on your own. </em>

x = 3.

Hence, the oxidation state on Cl is +3.

Ions carry charge. Oxidation states on atoms in an ion shall add up to the charge of the ion. The superscript of an ion shows its charge. The superscript 3- in the phosphate ion shows that the ion carries a charge of -3.

Oxidation states:

The oxidation state on P is to be found;
O: -2.

Let the oxidation state on P be x.

x + 4 × (-2) = -3;

x = 5.

Hence, the oxidation state on P is +5.

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