Answer:
Explanation:
Remark
You have 2 facts that you got from the experiment. The first is that the mass of the wood is 63.85 grams and the volume can be calculated.
From there, the desity can be found.
Givens
m = 63.85 grams
vo = 50 mL
vf = 125 mL
Solution
Volume = vf - vo
Volume = 125 mL - 50 ml. This gives you the amount of water that has been moved aside (called displaced)
volume = 75 mL
D = 63.85 grams/ 75 mL
D = 0.851 grams / mL
Some woods actually do have a density less than 1 which is the density of water. These woods float.
Pressure will decrease as volume increases, and vice-versa.
Answer:
mass HF = 150.05 g
Explanation:
- SiO2(s) + 4HF(g) → SiF4(g) + 2H2O(l)
⇒ Q = (ΔH°rxn * mHF) / (mol HF * MwHF )
∴ MwHF = 20.0063 g/mol
∴ mol HF = 4 mol
∴ ΔH°rxn = - 184 KJ
∴ Q = 345 KJ
mass HF ( mHF ):
⇒ mHF = ( Q * mol HF * MwHF ) / ΔH°rxn
⇒ mHF = ( 345 KJ * 4mol HF * 20.0063 g/mol ) / 184 KJ
⇒ mHF = 150.05 g HF
Answer:
17.55 g of NaCl
Explanation:
The following data were obtained from the question:
Molarity = 3 M
Volume = 100.0 mL
Mass of NaCl =..?
Next, we shall convert 100.0 mL to L. This can be obtained as follow:
1000 mL = 1 L
Therefore,
100 mL = 100/1000
100 mL = 0.1 L
Therefore, 100 mL is equivalent to 0.1 L.
Next, we shall determine the number of mole NaCl in the solution. This can be obtained as follow:
Molarity = 3 M
Volume = 0.1 L
Mole of NaCl =?
Molarity = mole /Volume
3 = mole of NaCl /0.1
Cross multiply
Mole of NaCl = 3 × 0.1
Mole of NaCl = 0.3 mole
Finally, we determine the mass of NaCl required to prepare the solution as follow:
Mole of NaCl = 0.3 mole
Molar mass of NaCl = 23 + 35.5 = 58.5 g/mol
Mass of NaCl =?
Mole = mass /Molar mass
0.3 = mass of NaCl /58.5
Cross multiply
Mass of NaCl = 0.3 × 58.5
Mass of NaCl = 17.55 g
Therefore, 17.55 g of NaCl is needed to prepare the solution.
Based on Heisenberg's uncertainty principle, the position and velocity of a particle cannot be determined simultaneously with accuracy.
In other words, Heisenberg's uncertainty principle states that the more accurately we know the position of a particle the less accurately we can know its velocity. Mathematically it is given as:
Δx.mΔv >= h/2π
where: Δx = uncertainty in position
m = mass
Δv = uncertainty in velocity
h = plancks constant
