Answer:
0.0428 kg or 42.8 g
Explanation:
Applying,
Q = cmΔt.............. Equation 1
Where Q = heat lost of heat gained, c = specific heat capacity of copper, m = mass of copper, Δt = temperature change.
make m the subject of the equation above
m = Q/cΔt.................. Equation 2
From the question,
Given: Q = 428 J, Δt = 25 °C
Constant: c = 400 J/kg.°C
Substitute these values into equation 2
m = 428/(25×400)
m = 0.0428 kg
m = 42.8 g
Answer:
Test tube one is a compound because it is 2 elements combine..Test tube to is an element
Explanation:
Answer:
No
Explanation:
One mole of P₄ react with six moles of I₂ and gives 4 moles of PI₃.
When one gram phosphorus and 6 gram of iodine react they gives 8.234 g
ram of PI₃ .
Given data:
Mass of phosphorus = 1 g
Mass of iodine = 6 g
Mass of PI₃ = ?
Solution:
Chemical equation:
P₄ + 6I₂ → 4PI₃
Number of moles of P₄:
Number of moles = Mass /molar mass
Number of mole = 1 g / 123.9 g/mol
Number of moles = 0.01 mol
Number of moles of I₂:
Number of moles = Mass /molar mass
Number of moles = 6 g / 253.8 g/mol
Number of moles = 0.024 mol
Now we will compare the moles of PI₃ with I₂ and P₄.
I₂ : PI₃
6 : 4
0.024 :
4/6×0.024 = 0.02
P₄ : PI₃
1 : 4
0.01 : 4 × 0.01 = 0.04 mol
The number of moles of PI₃ produced by I₂ are less it will be limiting reactant.
Mass of PI₃ = moles × molar mass
Mass of PI₃ = 0.02 mol × 411.7 g/mol
Mass of PI₃ = 8.234 g
Answer:
As solute concentration increases, vapor pressure decreases.
Step-by-step explanation:
As solute concentration increases, the number of solute particles at the surface of the solution increases, so the number of <em>solvent </em>particles at the surface <em>decreases</em>.
Since there are fewer solvent particles available to evaporate from the surface, the vapour pressure decreases.
C. and D. are <em>wrong</em>. The vapour pressure depends <em>only</em> on the number of particles. It does not depend on the nature of the particles.
A vertebrate has a backbone and invertebrates do not
