Answer:
They are composed of hydrogen and helium
Answer:
- There will be 1.23 moles of helium in the balloon at STP
Explanation:
1) <u>Initial conditions of the helium gas</u>:
- V = 20.0 liter
- p = 1.50 atm
- T = 25.0 °C = 25.0 + 273.15 K = 298.15 K
2) <u>Ideal gas equation</u>:
- pV = n RT
- p, V, and T are given above
- R is the Universal constant = 0.0821 atm-liter / ( K - mol)
- n is the unknown number of moles
3) <u>Solve for n</u>:
- n = 1.50 atm × 20.0 liter / (0.0821 atm-liter /k -mol ×298.15K)
4) <u>At STP:</u>
- STP stands for standard pressure and temperature.
- The amount (number of moles) of the gas will not change because the change of pressure and temperature, so the number of moles reamain the same: 1.23 mol.
It is easiest to tell if a solution is saturated if there is residue on the bottom. If it crystallized, the solution is saturated. If it is a supersaturated solution, there will not be crystallization unless more of the solute is added, at which point all of it will crystallize.
Weak base: [OH⁻] = √Kb.C
pKb = 4.2
c = concentration
MM Amphetamine (C9H13N) = 135.21 g/mol
c = 215 mg/L = (0.215 g : 135,21 g/mol) / L = 0.00159 mol/L = 1.59 x 10⁻³ mol/L
![\tt [OH^-]=\sqrt{10^{-4.2}\times 1.59\times 10^{-3}}=3.17\times 10^{-4}](https://tex.z-dn.net/?f=%5Ctt%20%5BOH%5E-%5D%3D%5Csqrt%7B10%5E%7B-4.2%7D%5Ctimes%201.59%5Ctimes%2010%5E%7B-3%7D%7D%3D3.17%5Ctimes%2010%5E%7B-4%7D)
pOH = 4 - log 3.17
pH = 14 - (4 - log 3.17)
pH = 10 + log 3.17 = 10.50
Answer:
280 mL
Explanation:
Given data:
Mass of CuSO₄ = 55.75 g
Molarity of CuSO₄ = 1.25 M
Volume of CuSO₄ = ?
Solution:
First of all we will calculate the number of moles.
Number of moles:
Number of moles = mass / molar mass
Number of moles = 55.75 g/ 159.6 g/mol
Number of moles = 0.35 mol
Volume of CuSO₄:
Molarity = number of moles / volume in litter
1.25 M = 0.35 mol / volume in litter
Volume in litter = 0.35 mol / 1.25 M
Volume in litter = 0.28 L
Volume in milliliter:
0.28 L × 1000 mL/ 1 L = 280 mL
