Answer:
Explanation:
This question asks us to find the new volume if the pressure changes. Therefore, we use Boyle's Law, which states that pressure and the volume of the gas are inversely proportional. The formula is:
We know that the original sample of gas occupies 4.5 liters at a pressure of 1.63 atmospheres. We know that the pressure was changed to 2.4 atmospheres, but we don't know the volume. Substitute all known values into the formula.
Since we are solving for the new volume (V₂), we need to isolate the variable. It is being multiplied by 2.4 atmospheres and the inverse of multiplication is division. Divide both sides by 2.4 atm.
The units of atmospheres (atm) cancel.
The smallest number of significant figures in the original measurements is 2, so our answer must have the same. For the number we found, that is the tenths place.
The 5 in the hundredth place tells us to round the 0 up to a 1.
The volume of the neon gas when the pressure is changed to 2.4 atmospheres is <u>3.1 Liters.</u>
<u>Question 1</u>
The formula mass of methanol is 
g/mol.
Therefore, in 5.0 grams of methanol, there are 
moles.
<u />
<u>Question 2</u>
The formula mass of copper(II) carbonate is 
g/mol.
This means that in 9.0 grams of copper(II) carbonate, there are 
moles.
Using Avogradro's number, there are 
molecules.
<u>Question 3</u>
The formula mass of cyclohexane is 
g/mol.
So, 3.0 grams of cyclohexane is the same as 
moles.
<u>Question 4</u>
The formula mass of benzene is 
g/mol.
This means that 4.00 moles of benzene has a mass of 
grams.
<u>Question 5</u>
1000 atoms of calcium is the same as 
moles.
This is equal to 
grams.
Answer:
Concentration: 0.185M HX
Ka = 9.836x10⁻⁶
pKa = 5.01
Explanation:
A weak acid, HX, reacts with NaOH as follows:
HX + NaOH → NaX + H2O
<em>Where 1 mole of HX reacts with 1 mole of NaOH</em>
To solve this question we need to find the moles of NaOH at equivalence point (Were moles HX = Moles NaOH).
18.50mL = 0.01850L * (0.20mol / L) = 0.00370 moles NaOH = Moles HX
In 20.0mL = 0.0200L =
0.00370 moles HX / 0.0200L = 0.185M HX
The equilibrium of HX is:
HX(aq) ⇄ H⁺(aq) + X⁻(aq)
And Ka is defined as:
Ka = [H⁺] [X⁻] / [HX]
<em>Where [H⁺] = [X⁻] because comes from the same equilibrium</em>
As pH = 2.87, [H+] = 10^-pH = 1.349x10⁻³M
Replacing:
Ka = [H⁺] [H⁺] / [HX]
Ka = [1.349x10⁻³M]² / [0.185M]
Ka = 9.836x10⁻⁶
pKa = -log Ka
<h3>pKa = 5.01</h3>
To calculate the number of moles, simply take the ratio of mass and molar mass. The molar mass of Iron (Fe) is equal to 55.85 g/mol.Therefore the total number of moles is:
moles Fe = 25.7 g / (55.85 g / mol)
moles Fe = 0.46 mole
