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antiseptic1488 [7]
3 years ago
6

Use lewis theory to determine the formula for the compound that forms between sr and se

Chemistry
1 answer:
katen-ka-za [31]3 years ago
4 0

\text{Sr}\text{Se}

<h3>Explanation</h3>

The Lewis Theory predicts the way atoms form bond based on their numbers of valence electrons. Atoms gain or lose electrons as they seek to achieve either a complete eight-electron valence shell or an empty shell, exposing the inner eight-electron shell. Both electron configurations are stable and are known as "octets". However, atoms tend to prefer the configuration with the minimum number of electron transfers.

Strontium (Sr) is found in group 2 (II A) of a modern periodic table. A neutral atom of strontium has two valence electrons in its valence shell.

Selenium (Se) is found in group 16 (VI A) of a modern periodic periodic table. A neutral atom of selenium contains six electrons in its valence shell.

Strontium needs to either lose two electrons or gain six electrons to achieve a configuration with eight electrons in its valence shell. Losing two electrons take less energy. Strontium is thus expected to lose two electrons.

Similarly, selenium would prefer gaining two electrons to losing six electrons. It is expected to gain two electrons.

As a result, a strontium atom would supply exactly two electrons. At the same time, a  As a result, a selenium atom would accept the two electrons, no more or no less. The two elements would combine at a one to one ratio. In other words:

n(\text{Sr, atoms}) : n(\text{Se, atoms}) \\= n(\text{Sr, electrons lost}) : n(\text{Se, electrons gained}) \\= 1:1

Each electron carries one negative charge. As a result, atoms that have gained electrons demonstrate a negative charge, whereas atoms that have lost electrons appear to be positive. By convention, atoms with a positive charge shall be written in front of those with a negative charge in a formula.

Sr atoms have lost electrons. Accordingly, they carry positive charges and shall be written at the beginning of the formula.

Se atoms have gained electrons. Accordingly, they carry negative charges and shall be placed to the end of the formula.

Thus the chemical formula: \text{Sr}\text{Se}

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A mixture of hept-1-yne, hept-2-yne, and hept-3-yne was hydrogenated in the presence of a platinum catalyst until hydrogen uptak
arsen [322]

Answer:

Only one seven carbon hydrocarbon was produced.

Explanation:

  • Alkynes are reduced completely in presence of Pt/H_{2} to produce alkanes.
  • Hydrogenation in presence of Pt is a simple nucleophilic addition process where H_{2} molecule adds onto an unsaturated bond.
  • Hept-1-yne, hept-2-yne and hept-3-yne are constitutionally isomeric to each other. Hence, after complete reduction, all three alkynes produced heptane as only product.
  • So, only one seven carbon hydrocarbon was produced.

4 0
2 years ago
For the reaction COCl2(g)⇌CO(g)+Cl2(g), K= 2.19×10−10 at 373 K
vladimir1956 [14]

Answer:

D) The equilibrium lies far to the left

Explanation:

According to the law of mass action, the equilibrium constant K for the reaction at 373K can be calculated as follows:

K = \frac{[CO][Cl_{2}]}{[COCl_{2}]} = 2.19×10^{-10}

([X] means = concentration of X)

This means that in the equilibrium the concentration of the reactant (that is in the denominator) will be much higher (around 10^{10} fold) than the concentrations of the products (that are in the numerator), and this means that the equilibrium lies far to the left (to the reactants side) as very small amount of product is being formed.

6 0
3 years ago
How many moles of chlorine gas are in 1.2m^3 at room temperature and pressure?
marshall27 [118]

Answer:

look it up lol

Explanation:

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5 0
3 years ago
100 PIONTSSSSS HELP ASAP
valina [46]

Left Panel

Short answer A

<em><u>Solution</u></em>

Since you have been given choices, my sloppy numbers will do, but it anyone is going to see this, YOU SHOULD CLEAN  THEM UP WITH THE NUMBERS THAT COME FROM YOUR PERIODIC TABLE.

Equation

Sodium Phosphate + Calcium Chloride ===> Sodium Chloride + Calcium Phosphate.

Na3PO4 + CaCl2 ===> NaCl + Ca3(PO4)2

<em><u>Step One</u></em>

Balance the Equation

2Na2PO4 + 3CaCl2 ==> 6NaCl + Ca3(PO4)2

<em><u>Step Two</u></em>

Find the molar mass of CaCl2

Ca = 40

2Cl = 71

Molar Mass = 40 + 71 = 111 grams/mole

<em><u>Step Three</u></em>

Find the number of moles of CaCl2

Given mass = 379.4

Molar Mass = 111

moles = given Mass / molar Mass

moles of CaCl2 = 379.4/111 = 3.418 moles

<em><u>Step Four</u></em>

Find the number of moles of Ca3(PO4)2 needed.

This requires that you use the balance numbers from the balanced equation.

For every 3 moles of CaCl2 you have, you get 1 mole of Ca3(PO4)2

n_moles of Ca3(PO4)2 = 3.418 / 3 = 1.13933 moles

<em><u>Step Five</u></em>

Find the molar mass of Ca3(PO4)2

From the periodic table,

3Ca = 3 * 40 = 120

2 P  = 2 * 31 =    62

8 O = 8 * 16   =128

Molar Mass = 120 + 62 + 128= 310 grams per mole.

<em><u>Step Six</u></em>

1 mole of Ca3(PO4)2 has a molar mass of 310 gram

1.13933 moles of Ca3(PO4)2 = x

x = 1.13933 moles * 310 grams /mole

x = 353.2 grams. As you can see, even with my rounding I'm only out 0.3 of a gram. DON'T FORGET TO PUT THIS TO THE PROPER SIG DIGS IF SOMEONE ELSE IS GOING TO SEE IT.

Middle Panel

Short Answer C

Equation

2HCl + Mg ===> H2 + MgCl2

The object of the first part of the game is to find the number of moles of H2.

<em><u>Step One</u></em>

Find the moles of HCl

1 mole HCl = 35.5 + 1 = 36.5

n = given mass divided by molar mass

n = 49 grams / 36.5 = 1.34 moles.

The balanced equation tells you that for ever mole of H2 produced, you need 2 moles of HCl. That's what the balance numbers are for.

So the number of moles of H2 is 1.34 / 2 = 0.671 moles of H2.

Now we come to Part II. We have to use an new friend of yours that I have seen only once before from you.

Find V using PV = nRT

R is going to be in kPa so the value of R = 8.314

V = ???

n = 0.671 moles

T = 25 + 273 = 298oK

P = 101.3 kPa

101.3 * V= 0.671*8.314 * 298

V = 0.671 * 8.314 * 298 / 101.3

V = 16.4

The answer is C and again, I have rounded almost everything except R, although it can go out to 8 places.

Right Panel

I can't see the panel. I don't know what the problem is. Never mind I got it. I'm going to be a little skimpy on this one since I've done two like it and they are long.

LiOH + HBr ===> LiBr + H2O and the equation is balanced.

You have to figure out the moles of LiOH and HBr. Use the LOWEST number of moles

n_LiOH = given mass / molar mass = 117/(7 + 16 + 1) = 117 / 24 = 4.875 moles

n_HBr = given mass / molar mass =  141/(1 + 80) = 141 / 81 = 1.741 moles

HBr is the lower number. That's all the LiBr you are going to get is 1.741. There is no adjustment to be made from the balance equation.

n = given mass / molar mass  multiply both sides by the molar mass

n * Molar mass (LiBr) = n * (7 + 80) = 1.741 * 87 = 151 grams of

The answer is C


6 0
2 years ago
Need help on this question asap pleasee
algol [13]

Answer:

9.0 moles of CaO

Explanation:

We have the reaction equation as follows;

Fe2O3 + Ca3(PO4)2 -------> 2FePO4 + 3CaO

Now we know from the equation that;

1 mole of iron III oxide yields 3 moles of CaO

Therefore;

3 moles of iron III oxide yields 3 * 3/1

= 9.0 moles of CaO

6 0
2 years ago
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