Answer:
Phosphorus has a low melting point because the intramolecular forces holding it together is London Dispersion Forces.
Explanation:
London Dispersion Forces (LDF) are the weakest intramolecular forces. You don't need to break the covalent bonds, but rather the Van Der Waals' Forces. If LDF are the weakest forces, then the melting point is low.
Hey there!
* Converts 1750 dm³ in liters :
1 dm³ = 1 L so 1750 dm³ = 1750 liters
* Convertes 125,000 Pa in atm :
1 Pa = 9.86*10⁻⁶ atm so 9.86*10⁻⁶ / 125,000 => 1.233 atm
* Convertes 127ºC in K :
127 + 273.15 => 400.15 K
R = 0.082 atm.L/mol.K
Finally, it uses an equation of clapeyron :
p * V = n * R * T
1.233 * 1750 = n * 0.082 * 400.15
2157.75 = n * 32.8123
n = 2157.75 / 32.8123
n = 65.76 moles
hope this helps!
Answer:

Explanation:
Hello,
In this case, since the undergoing chemical reaction is:

The corresponding moles of carbon dioxide occupying 40.0 mL (0.0400 L) are computed by using the ideal gas equation at 273.15 K and 1.00 atm (STP) as follows:

Then, since the mole ratio between carbon dioxide and calcium carbonate is 1:1 and the molar mass of the reactant is 100 g/mol, the mass that yields such volume turns out:

Regards.