Answer:
Galileo discovered that objects that are more dense, or have more mass, fall at a faster rate than less dense objects, due to this air resistance. A feather and a rubber ball dropped together. Air resistance causes the feather to fall more slowly, while the ball falls more fast.
<u>Answer:</u> The molality of potassium hydroxide solution is 0.608 m
<u>Explanation:</u>
We are given:
3.301 mass % of potassium hydroxide solution.
This means that 3.301 grams of potassium hydroxide is present in 100 grams of solution
Mass of solvent = Mass of solution - Mass of solute (KOH)
Mass of solvent = (100 - 3.301) g = 96.699 g
To calculate the molality of solution, we use the equation:
Where,
= Given mass of solute (KOH) = 3.301 g
= Molar mass of solute (KOH) = 56.1 g/mol
= Mass of solvent = 96.699 g
Putting values in above equation, we get:
Hence, the molality of potassium hydroxide solution is 0.608 m
Answer:
25.2°C
Explanation:
Given parameters:
Energy applied to the water = 1000J
Mass of water = 50g
Final temperature = 30°C
Unknown:
Initial temperature = ?
Solution:
To solve this problem, we use the expression below:
H = m c Ф
H is the energy absorbed
m is the mass
c is the specific heat capacity
Ф is the change in temperature
1000 = 50 x 4.184 x (30 - initial temperature )
1000 = 209.2(30 - initial temperature)
4.78 = 30 - initial temperature
4.78 - 30 = - initial temperature
Initial temperature = 25.2°C
Moles He = 7.83 x 10^24 / 6.02 x 10^23 =13.0
<span>mass He = 13.0 mol x 4.00 g/mol = 52.0 g</span>
