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3 years ago

How to I find the number of electrons in and Atom?

1 answer:

8 0

Look at the atomic number of an element on the periodic table which is the smaller number.
The atomic number shows the number of protons/electrons so the number of protons and electrons are the same.
Whereas the mass number of an element (the other number) is the number of protons + neutrons.

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Which of the following metals is soluble in water with S2-?

Brut [27]

Strontium is soluble with s2-

6 0

3 years ago

Directions: Read through each scenario and identify the independent variable, dependent variable, and the control.

podryga [215]

Answer:

The correct answer is - brand of floor wax.

Explanation:

The independent variable is the variable or the factor in an investigation which is manipulated or change in the experiment and affects the dependent variable and produces a various result.

In this investigation, there are different brands of the floor was are the independent variable as they are changed to see the effect on the scratches on the floor on 20 tiles for each brand.

5 0

3 years ago

What is the % yield when 140.0 grams of Ethylene gas (C2H4) reacts with excess chlorine to form 280.0 grams of 1,2-Dichloro Etha

KatRina [158]

Answer:

percent yield = 56.6 %

Explanation:

Data given:

mass of Ethylene gas (C₂H₄) = 140 g

actual yield of 1,2-Dichloro Ethane (C₂H₄Cl₂)= 280 g

percent yield of 1,2-Dichloro Ethane (C₂H₄Cl₂) = ?

Reaction Given:

C₂H₄ + Cl₂ -------> C₂H₄Cl₂

Solution:

First we have to find theoretical yield.

So,

Look at the reaction

C₂H₄ + Cl₂ -----—> C₂H₄Cl₂

1 mol 1 mol

As 1 mole of C give 1 mole of CH₄

Convert moles to mass

molar mass of C₂H₄ = 2(12) + 4(1)

molar mass of C₂H₄ = 24 + 4

molar mass of C₂H₄ = 28 g/mol

molar mass of C₂H₄Cl₂ = 2(12) + 4(1) + 2(35.5)

molar mass of C₂H₄Cl₂ = 24 + 4 + 71

molar mass of C₂H₄Cl₂ = 99 g/mol

Now

C₂H₄ + Cl₂ -----—> C₂H₄Cl₂

1 mol (28 g/mol) 1 mol (99 g/mol)

28 g 99 g

28 grams of Ethylene gas (C₂H₄) produce 99 grams of C₂H₄Cl₂

if 28 g of C₂H₄ produce 99 g of C₂H₄Cl₂ so how many grams of C₂H₄Cl₂ will be produced by 140 g of C₂H₄.

Apply Unity Formula

28 g of C₂H₄ ≅ 99 g of C₂H₄Cl₂

140 g of C₂H₄≅ X of C₂H₄Cl₂

Do cross multiply

mass of C₂H₄Cl₂ = 99 g x 140 g / 28 g

mass of C₂H₄Cl₂ = 495 g

So the Theoretical yield of 1,2-Dichloro Ethane (C₂H₄Cl₂)= 495 g

Now Find the percent yield of 1,2-Dichloro Ethane (C₂H₄Cl₂)

Formula Used

percent yield = actual yield /theoretical yield x 100 %

Put value in the above formula

percent yield = 280g / 495 g x 100 %

percent yield = 56.6 %

percent yield of 1,2-Dichloro Ethane (C₂H₄Cl₂) = 56.6 %

8 0

4 years ago

At a certain temperature, 0.660 mol SO 3 is placed in a 4.00 L container. 2 SO 3 ( g ) − ⇀ ↽ − 2 SO 2 ( g ) + O 2 ( g ) At equil

svet-max [94.6K]

Answer:

$Kc=6.875x10^{-3}$

Explanation:

Hello,

In this case, for the given chemical reaction at equilibrium:

$2 SO_3 ( g ) \rightleftharpoons 2 SO_ 2 ( g ) + O_ 2 ( g )$

The initial concentration of sulfur trioxide is:

$[SO_3]_0=\frac{0.660mol}{4.00L}=0.165M$

Hence, the law of mass action to compute Kc results:

$Kc=\frac{[SO_2]^2[O_2]}{[SO_3]^2}$

In such a way, in terms of the change $x$ due to the reaction extent, by using the ICE method, it is modified as:

$Kc=\frac{(2x)^2*x}{(0.165-2x)^2}$

In that case, as at equilibrium 0.11 moles of oxygen are present, $x$ equals:

$x=[O_2]=\frac{0.110mol}{4.00L}=0.0275M$

Therefore, the equilibrium constant finally turns out:

$Kc=\frac{(2*0.0275)^2*0.0275}{(0.165-2*0.0275)^2} \\\\Kc=6.875x10^{-3}$

Best regards.

6 0

3 years ago

How many grams are in 3.1 moles of H2SO4?

Mkey [24]

Answer:

98.07848 grams.

Explanation:

6 0

3 years ago