Answer:
100g/mol
Explanation:
Given parameters:
Mass of unknown gas = 2g
Volume of gas in flask = 500mL = 0.5dm³
Unknown:
Molar mass of gas = ?
Solution:
Since we know the gas is at STP;
1 mole of substance occupies 22.4dm³ of space at STP
Therefore,
0.5dm³ will have 0.02mole at STP
Now;
Number of moles = 
Molar mass = 
= 
= 100g/mol
Answer: Molarity of 
in the original sample was 1.96M
Explanation:
Molarity is defined as the number of moles of solute dissolved per liter of the solution.
Now put all the given values in the formula of molarity, we get
Thus molarity of in the original sample was 1.96M
Answer:
1.505×10^23 atoms of lead
Explanation:
Volume of lead in the lungs = total volume of lungs = 5.60L
1 mole = 22.4L
5.6L of lead = 5.6/22.4 = 0.25 mole
From Avogadro's law
1 mole of lead contains 6.02×10^23 atoms of lead
0.25 mole of lead = 0.25×6.02×10^23 = 1.505×10^23 atoms of lead
It's a cube so the volume = edge^3
Volume = 2.5^3 cm^3 = 15.625 cm^3
density = mass / volume = 42.20 / 15.625 = 2.70 You have 3 places of accuracy.
density of object = 2.70 grams / cm^3 <<<<=== answer.
for HClO, pKa = 7.54
for HNO_2, pKa = 3.15
for CH3 COOH, pKa = 4.74
Explanation:
The concentration of the solution given is 0.1 M has a pH closest to 7
The mixtures are weak acids and their salts except
HNO_3 and NaNO_3 pH = pH is near to '1'
for buffers( acidic) pH = pKa + log [salt] / [acid]
therefore [salt] = [acid] = 0.1 pH = pKa + log 0.1 / 0.1 = pKa
pH = pKa
for HClO, pKa = 7.54
for HNO_2, pKa = 3.15 therefore HClO and NaclO
mixture hs a pH closest to '7'
for CH3 COOH, pKa = 4.74
