A penny for the scratch test (low hardness)a hand lens for inspection a peice of tile for a streak test a geologic hammer to test for cleavage of fracture and the pocket knife for the scratch test (high hardness)
Answer:
when the solution is heated and reaches its saturation point thus starts forming crystals thus crystals starts forming hence crystallisation takes place
Answer: 996 mmHg
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at NTP, weighs equal to the molecular mass and contains avogadro's number of particles.
According to the ideal gas equation:
P = Pressure of the gas = ?
V= Volume of the gas = 25.5 L
T= Temperature of the gas = 13°C = (273+13) K = 286K
R= Gas constant = 0.0821 atmL/K mol
n= moles of gas= 1.42
(760mmHg=1atm)
Thus pressure of this gas sample is 996 mm Hg.
16.94 % Zn
Explanation:
First we need the molar weight of the Zn₃(PO₄)₂:
molar weight of Zn₃(PO₄)₂ = atomic weight of Zn × 3 + atomic weight of P × 2 + atomic weight of O × 4 × 2
molar weight of Zn₃(PO₄)₂ = 65.4 × 3 + 31 × 2 + 16 × 4 × 2 = 386 g/moles
Taking in account weight of 1 mole of Zn₃(PO₄)₂ we devise the following reasoning:
if 386 g of Zn₃(PO₄)₂ contains 65.4 g of Zn
then 100 g of Zn₃(PO₄)₂ contains X g of Zn
X = (100 × 65.4) / 386 = 16.94 % Zn
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