The mass fraction of sodium chloride is 0.0625
<h3>What is the mass fraction of sodium chloride in the solution?</h3>
The mass fraction of sodium chloride is the ratio of the mass of sodium chloride to the total mass of the solution.
The mass fraction of sodium chloride is determined as follows;
mass of sodium chloride = 20 g
- mass of water = volume * density
density of water = 1 g/mL
volume of water = 300 mL
mass of water = 300 mL * 1 g/mL
mass of water = 300 g
total mass of solution = 20 + 300 = 320 g
mass fraction of sodium chloride = 20/320
mass fraction of sodium chloride = 0.0625
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How many protons are in an isotope of sodium with a mass number of 25? 11
Answer:
Protons: 79
Electrons: 78
Explanation:
1. The number of protons is the atomic number (The atomic number for Au on the periodic table is 79)
2. Since the charge is +1 (positive) it means that there's one more proton than electrons. So, 79-1 = 78 electrons
Given:
Ma = 31.1 g, the mass of gold
Ta = 69.3 °C, the initial temperature of gold
Mw = 64.2 g, the mass of water
Tw = 27.8 °C, the initial temperature of water
Because the container is insulated, no heat is lost to the surroundings.
Let T °C be the final temperature.
From tables, obtain
Ca = 0.129 J/(g-°C), the specific heat of gold
Cw = 4.18 J/(g-°C), the specific heat of water
At equilibrium, heat lost by the gold - heat gained by the water.
Heat lost by the gold is
Qa = Ma*Ca*(T - Ta)
= (31.1 g)*(0.129 J/(g-°C)(*(69.3 - T °C)-
= 4.0119(69.3 - T) j
Heat gained by the water is
Qw = Mw*Cw*(T-Tw)
= (64.2 g)*(4.18 J/(g-°C))*(T - 27.8 °C)
= 268.356(T - 27.8)
Equate Qa and Qw.
268.356(T - 27.8) = 4.0119(69.3 - T)
272.3679T = 7738.32
T = 28.41 °C
Answer: 28.4 °C
NaPO4 + KOH -> KPO4 + NaOH
already balance
