Answer:
Fluorine, chlorine, bromine and iodine are grouped together because they have the same number of valence electrons.
Explanation:
Fluorine, chlorine, bromine and iodine are all found in group 7, which is the second-last column from the right. Group 7 elements are also called the "Halogens" family.
The group number also tells you the number of valence electrons that the elements have in that group. Valence electrons mean the outermost electrons (See picture).
For example, fluorine has two shells (the circles with dots on them). The outermost electrons, or valence electrons, are the dots on the biggest circle. There are 7 dots, so there are 7 valence electrons, which corresponds with Group "7".
A full shell (except the for first shell) is when there are 8 dots. Since 7 is so close to 8, Halogens are very reactive.
Fluorine, chlorine, bromine and iodine all have 7 valence electrons and are in the Halogens family, which are very reactive.
<u>Answer: </u>The correct answer is 1.32 mol 
<u>Explanation:</u>
For the reaction of lithium and hydrofluoric acid, the equation follows:
By Stoichiometry of the reaction:
if 2 moles of lithium is producing 1 mole of hydrogen gas,
Then, 3.50 moles of lithium will produce = 
of hydrogen gas.
- Now, to know the theoretical yield of hydrogen gas, we use the equation:
...(1)
Moles of hydrogen gas = 1.75 mol
Molar mass of hydrogen gas = 2 g/mol
Putting values in above equation, we get:
- To calculate the percentage yield, we use the equation:
Percentage yield = 75.5 %
Theoretical yield = 3.5 g
Putting values in above equation, we get:
- Now, calculating the moles of hydrogen gas, we put the value in equation 1, we get:
Hence, the correct answer is 1.32 mol
Answer:
The new volume of the balloon when the pressure equalised with the pressure of the atmosphere = 494 L.
The balloon expands by am additional 475 L.
Explanation:
Assuming Helium behaves like an ideal gas and temperature is constant.
According to Boyle's law for ideal gases, at constant temperature,
P₁V₁ = P₂V₂
P₁ = 26 atm
V₁ = 19.0 L
P₂ = 1 atm (the balloon is said to expand till the pressure matches the pressure of the atmpsphere; and the pressure of the atmosphere is 1 atm)
V₂ = ?
P₁V₁ = P₂V₂
(26 × 19) = 1 × V₂
V₂ = 494 L (it is assumed the balloon never bursts)
The new volume of the balloon when the pressure equalised with the pressure of the atmosphere = 494 L.
The balloon expands by am additional 475 L.
Hope this Helps!!!
Answer: W + BgCz2 arrow WCz + Bg
2 W + BgCz2 arrow 2 WCz + Bg
Explanation:
Cz has 2 so you balcne the other side of WCz.
Since you Balcanes the Cz you changed the W and you Balcanes the other W on the left side.
Answer:
a) The theoretical yield is 408.45g of 
b) Percent yield = 
Explanation:
1. First determine the numer of moles of 
and 
.
Molarity is expressed as:
M=
- For the
M=
Therefore there are 1.75 moles of
- For the
M=![\frac{2.0moles[tex]Na_{2}SO_{4}](https://tex.z-dn.net/?f=%5Cfrac%7B2.0moles%5Btex%5DNa_%7B2%7DSO_%7B4%7D)
}{1Lsolution}[/tex]
Therefore there are 2.0 moles of
2. Write the balanced chemical equation for the synthesis of the barium white pigment, :
3. Determine the limiting reagent.
To determine the limiting reagent divide the number of moles by the stoichiometric coefficient of each compound:
- For the :
- For the :
As the is the smalles quantity, this is the limiting reagent.
4. Calculate the mass in grams of the barium white pigment produced from the limiting reagent.
5. The percent yield for your synthesis of the barium white pigment will be calculated using the following equation:
Percent yield = 
Percent yield =
The real yield is the quantity of barium white pigment you obtained in the laboratory.
