Answer:
0.46875g/ml
Explanation:
Density(p) = m / v unit - g/ml or Kg/m^3
Given
mass = 2.4g
volume = 5.12ml
p = m / v
= 2.4g / 5.12ml
= 0.46875g/ml
Answer:
covalent bonds
Explanation:
A chemical bond is a lasting attraction between atoms that enables the formation of chemical compounds and may result from the electrostatic force of attraction between atoms with opposite charges, or through the sharing of electrons as in the covalent bonds.
Maybe by protons i forgot how to spell it :(
Here we have to calculate the heat required to raise the temperature of water from 85.0 ⁰F to 50.4 ⁰F.
10.857 kJ heat will be needed to raise the temperature from 50.4 ⁰F to 85.0 ⁰F
The amount of heat required to raise the temperature can be obtained from the equation H = m×s×(t₂-t₁).
Where H = Heat, s =specific gravity = 4.184 J/g.⁰C, m = mass = 135.0 g, t₁ (initial temperature) = 50.4 ⁰F or 10.222 ⁰C and t₂ (final temperature) = 85.0⁰F or 29.444 ⁰C.
On plugging the values we get:
H = 135.0 g × 4.184 J/g.⁰C×(29.444 - 10.222) ⁰C
Or, H = 10857.354 J or 10.857 kJ.
Thus 10857.354 J or 10.857 kJ heat will be needed to raise the temperature.
Answer:
-800 kJ/mol
Explanation:
To solve the problem, we have to express the enthalpy of combustion (ΔHc) in kJ per mole (kJ/mol).
First, we have to calculate the moles of methane (CH₄) there are in 2.50 g of substance. For this, we divide the mass into the molecular weight Mw) of CH₄:
Mw(CH₄) = 12 g/mol C + (1 g/mol H x 4) = 16 g/mol
moles CH₄ = mass CH₄/Mw(CH₄)= 2.50 g/(16 g/mol) = 0.15625 mol CH₄
Now, we divide the heat released into the moles of CH₄ to obtain the enthalpy per mole of CH₄:
ΔHc = heat/mol CH₄ = 125 kJ/(0.15625 mol) = 800 kJ/mol
Therefore, the enthalpy of combustion of methane is -800 kJ/mol (the minus sign indicated that the heat is released).
