Answer: 0.043g
Explanation:
chemical formular of perchloric acid is HClO4
no. of moles = mass / molar mass
n = m / mm
m = n x mm
n = 4.25 x 10^-4 mol
m = ?
mm = 1 + 35.5 + (16 x 4) = 100.5g/mol
m = 4.25 x 10^-4 mol x 100.5g/mol
m = 0.043g
Answer:
A) 900 J
B) 27.96 J
C) 1,628 J ≅ 1.63 kJ
Explanation:
The heat absorbed by the metal (silver) - or energy required to heat it - is calculated as:
heat = mass x Cp x ΔT
Where Cp is the heat capacity (0.24 J/°C ·g) and ΔT is the change in temperature (final T - initial T).
A) Given:
mass = 150.0 g
final T = 298 K = 25°C
initial T = 273 K = 0°C
We calculate the energy in J to raise the temperature:
heat = mass x Cp x (final T - initial T)
= 150 .0 g x 0.24 J/°C ·g x (25°C - 0°C )
= 900 J
B) Given:
moles Ag= 1.0 mol
ΔT = 1.08°C
We first calculate the mass of silver (Ag) by multiplying the moles of Ag by the molar mass of Ag (MM = 107.9 g/mol)
mass = moles x MM = 1.0 mol Ag x 107.9 g/mol Ag = 107.9 g
Then, we calculate the heat required:
heat = mass x Cp x ΔT = 107.9 g x 0.24 J/°C ·g x 1.08°C = 27.96 J
C) Given:
heat = 1.25 kJ = 1,250 J
final T = 15.28°C
initial T = 12.08°C
We first calculate the change in temperature:
ΔT = final T - initial T = 15.28°C - 12.08°C = 3.2°C
Then, we calculate the mass of silver:
mass = heat/(Cp x ΔT) = 1,250 J/(0.24 J/°C ·g x 3.2°C) = 1,628 J ≅ 1.63 kJ
Answer:
9 (1-2x²)
Explanation:
The given expression is:
30 - 9x²*2 - 21 - 4 + 4
The first step is to compute the multiplication. This will give:
30 - 18x² - 21 - 4 + 4
Then, we will add like terms as follows:
(30-21-4+4) - 18x²
= 9 - 18x²
Finally, we can take the 9 as a common factor from both terms, this will give:
9 (1-2x²)
Hope this helps :)
They both conduct electricity at least partially
