We know it’s C because of what it says in the text
Use the Ideal Gas Law to find the moles of gas first.
Be sure to convert T from Celsius to Kelvin by adding 273.
Also I prefer to deal with pressure in atm rather than mmHg, so divide the pressure by 760 to get it in atm.
PV = nRT —> n = PV/RT
P = 547 mmHg = 547/760 atm = 0.720 atm
V = 1.90 L
T = 33°C = 33 + 273 K = 306 K
R = 0.08206 L atm / mol K
n = (0.720 atm)(1.90 L) / (0.08206 L atm / mol K)(306 K) = 0.0545 mol of gas
Now divide grams by mol to get the molecular weight.
3.42 g / 0.0545 mol = 62.8 g/mol
Answer:
0.4033 M is the concentration of the sodium hydroxide solution.
Explanation:
Mass of potassium hydrogen phthalate = 2.023 g
Molar mass of potassium hydrogen phthalate = 204.22 g/mol
Moles of potassium hydrogen phthalate :
= 
According to reaction, 1 mole of potassium hydrogen phthalate reacts with 1mole of NaOH. Then 0.009906 moles of potassium hydrogen phthalate will recat with:
of NaOH
Moles of NaOH = 0.009906 mol
Volume of NaOH solution = 24.56 mL = 0.02456 L
![[NaOH]=\frac{0.009906 mol}{0.02456 L}=0.4033 M](https://tex.z-dn.net/?f=%5BNaOH%5D%3D%5Cfrac%7B0.009906%20mol%7D%7B0.02456%20L%7D%3D0.4033%20M)
0.4033 M is the concentration of the sodium hydroxide solution.
Answer:
When the solution (with phenolphthalein) changes to colorless
Explanation:
When titrating with HCl is common to add phenolphthalein as an acid-base indicator.
Phenolphthalein is pink or fucsia when added into a basic solution. On the other hand when it is in acid solutions, is colorless.
So, when titrating, the NaOH solution will be initialy pink due to the phenolphthalein and when reaching the equivalence point, that color will fade out into colorless. This is how you know you hace reached the equivalent point.
