Answer:
142.82 g
Explanation:
The following data were obtained from the question:
Volume of water = 12 mL
Volume of water + gold = 19.4 mL
Density of gol= 19.3 g/cm³
Mass of gold =.?
Next, we shall determine the volume of the gold. This can be obtained as follow:
Volume of water = 12 mL
Volume of water + gold = 19.4 mL
Volume of gold =.?
Volume of gold = (Volume of water + gold) – (Volume of water)
Volume of gold = 19.4 – 12
Volume of gold = 7.4 mL
Finally, we shall determine the mass of the gold as follow:
Note: 1 mL is equivalent to 1 cm³
Volume of gold = 7.4 mL
Density of gol= 19.3 g/cm³ = 19.3 g/mL
Mass of gold =?
Density = mass /volume
19.3 = mass of gold /7.4
Cross multiply
Mass of gold = 19.3 × 7.4
Mass of gold = 142.82 g
Therefore, the mass of the gold pebble is 142.82 g
16 g. The mass of 0.60 mol Al is 16 g.
Molar mass of Al = 26.98 g/mol
Mass of Al = 0.60 mol Al x (26.98 g Al/1 mol Al) = 16 g Al
Answer:
R = 40 ohms
Explanation:
Given that,
The voltage of outlet, V = 120 V
Current flowing through the device, I = 3 A
We need to find the Resistance rating of the power cord. Let the resistance is R. We know that,
Ohm's law, V = IR
Put all the values,
So, the resistance rating of the power cord is equal to 40 ohms.
A controlled variable is essentially what is kept the same throughout the whole experiment.
Answer:
Option 1 is correct.
ΔH for the condensation of 1 kg of Acetone is - 501 KJ.
Explanation:
Molar mass of acetone = 58.08 g/mol
Number of moles of acetone that condenses = mass/molar mass = 1000/58.08 = 17.22 moles
1 mole of Acetone vaporizer with an enthalpy change of 29.1 KJ.
1 mole of Acetone will condense with an enthalpy change of - 29.1 KJ (since condensation is the exact reverse of vaporization)
That is, vaporization is given by,
Acetone(l) ----> Acetone(g) ΔH = 29.1 KJ
Then condensation will be given by,
Acetone(g) ----> Acetone(l) ΔH = -29.1 KJ
So,
1 mole of Acetone will condense with an enthalpy change of - 29.1 KJ
17.22 moles of Acetone will condense with an enthalpy change of 17.22 × - 29.1 KJ = - 501 KJ.
The first option is correct.
