1 carat -------------- 200 mg
44.4 carat ---------- ( mass diamond )
mass = 44.4 x 200 / 1
mass = 8880 mg
1 g ------------------------ 1000 mg
( mass in grams) --------- 8880 mg
mass in grams = 8880 x 1 / 1000
mass in grams = 8880 / 1000
= 8.88 g
Answer:
-171.79 KJ
Explanation:
We must keep in mind that water freezes at 0 degrees centigrade
Recall that heat lost during freezing can be obtained from;
H = mc(θ2 - θ1)
m = mass of the water = 350 g/1000 = 0.35 Kg
c = specific heat capacity of water = 4,200 J/kg°C
θ2 = final temperature = 0°C
θ1 = initial temperature = 37°C
H= 0.35 * 4,200 * (0 - 37)
H = -54390 J = -54.39 KJ
Energy given out when 1 mole of water freezes at its freezing point = -6.04 kJ
For 350 g of water; 350 g/18 g/mol * -6.04 kJ = -117.4 kJ
Hence total energy removed = (-54.39 KJ) + (-117.4 kJ) = -171.79 KJ
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Since f is positive I would say f
Answer:
3.861x10⁻⁹ mol Pb⁺²
Explanation:
We can <u>define ppm as mg of Pb²⁺ per liter of water</u>.
We<u> calculate the mass of lead ion in 100 mL of water</u>:
- 100.0 mL ⇒ 100.0 / 1000 = 0.100 L
- 0.100 L * 0.0080 ppm = 8x10⁻⁴ mg Pb⁺²
Now we <u>convert mass of lead to moles</u>, using its molar mass:
- 8x10⁻⁴ mg ⇒ 8x10⁻⁴ / 1000 = 8x10⁻⁷ g
- 8x10⁻⁷ g Pb²⁺ ÷ 207.2 g/mol = 3.861x10⁻⁹ mol Pb⁺²