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IrinaVladis [17]
3 years ago
8

Which element is located in period 4?

Chemistry
1 answer:
Lena [83]3 years ago
6 0

Answer:

i beleive iron

Explanation:

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How many moles are in 7.8g of CaO?
Bess [88]

This compound is also known as Calcium Oxide. The SI base unit for amount of substance is the mole. 1 grams CaO is equal to 0.017832495800447 mole. Note that rounding errors may occur, so always check the results.

Hope I helped :)

4 0
3 years ago
For the following reaction, 4.34 grams of sulfur dioxide are mixed with excess oxygen gas . The reaction yields 3.89 grams of su
Degger [83]

Answer:

5.42g, 71.77%

Explanation:

First, we have to write out the balanced chemical equation. The unbalanced equation can be written as “SO2+O2 -> SO3” and to balance it, we can see that having two mols of SO2 and two mols of SO3 will make each side have the same amount of mols per element on each side. So the balanced chemical equation is “2SO2 + O2 -> 2SO3”

Now, we want to solve for the theoretical yield in grams of SO3. To do this, we have to use dimensional analysis. We convert g SO2 into mols SO2 using the molar mass of the elements. Then we convert mols of SO2 into mols of SO3 using the balanced equation. Once we’ve done that, we can convert mols of SO3 into grams of SO3.

You should know how to look up the molar mass of elements on the periodic table by now. Find the masses and set up the terms so they cancel like so:

4.34g \times  \frac{1mol \: so2}{64.07g \: so2}  \times  \frac{2 \: mol \: so3}{2 \: mol \: so2}  \times  \frac{80.07gso3}{1 \: mol \: so3}

Doing the math, we get 5.42g so3 as the theoretical yield. This is the most amount that you could ever get if the world was a perfect place. But alas, it isn’t and mistakes are gonna happen, so the number is going to be less than that. So the best we can do, is to figure out the percent yield that we got.

In a lab scenario, this was calculated to be 3.89 g as stated by the problem. The percent composition formula is

| \frac{result}{expected \: result} |  \times 100

and plugging the numbers into it, we get:

| \frac{3.89}{5.42} |  \times 100 = 71.77\%

make sure to follow the decimal/significant figure rules of your instructor, but only round at the end. My professor didn't care too much thankfully, but some professors do

6 0
2 years ago
An ethylene gas torch requires 300 L of gas at 0.8 atm. What will be the pressure of the gas if ethylene is supplied by a 200.0
Vlad [161]

Answer:

1.2 atm

Explanation:

Given data

  • Volume of the gas in the tank (V₁): 200.0 L
  • Pressure of ethylene gas in the tank (P₁): ?
  • Volume of the gas in the torch (V₂): 300 L
  • Pressure of the gas in the torch (P₂): 0.8 atm

If we consider ethylene gas to be an ideal gas, we can find the pressure of ethylene gas in the tank using Boyle's law.

P_1 \times V_1 = P_2 \times V_2\\P_1 = \frac{P_2 \times V_2}{V_1} = \frac{0.8atm \times 300L}{200.0L} = 1.2 atm

3 0
3 years ago
How many valence electrons do the alkaline earth metals have?
fenix001 [56]

Answer:

\boxed{2}

Explanation:

Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.

5 0
3 years ago
Read 2 more answers
Given the setup of the equilibrium constant expression, a reaction that has a high equilibrium constant will "favor" the product
ss7ja [257]

Answer:

for points

Explanation:

loll

5 0
3 years ago
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