Answer:
- 13,150.6kJ
Explanation:
CH4 + 2 O2 ------> CO2 + 2 H2O ΔH= – 890 kJ
The ΔH is enthalpy change of combustion , which is the heat is either absorbed or released by the combustion of one mole of a substance.
ΔH=−890 kJ/mol (released in the combustion of one mole of methane)
using the molar mass (in grams )of methane to get moles of sample
(237g × 1 mole of CH4)/16.04g=14.776 moles of CH4
Since 1 mole produces 890 kJ of heat upon combustion, then 14.776 moles will produce
ΔH = 14.776moles of CH4 × 890kJ/1mole of CH4
=13,150.6kJ
Therefore ΔH = - 13,150.6kJ
Answer:
c. 15 g Kr
Explanation:
The amount of a gas (Moles) is directely proportional to its pressure. That means the higher amount of moles, the highest pressure and vice versa.
Using molar mass of the compounds (Ne=20.2g/mol, Ar = 39.9g/mol, Kr = 83.8g/mol, CO₂ = 44 g/mol and F₂ = 38.0g/mol), moles of 15.0g of each gas are:
Ne = 15g ₓ (1mol / 20.2g) = <em>0.74 moles of Ne</em>
Ar = 15g ₓ (1mol / 39.9g) = <em>0.38 moles of Ar</em>
Kr = 15g ₓ (1mol / 83.8g) = <em>0.18 moles of Kr</em>
CO₂ = 15g ₓ (1mol / 44g) = <em>0.34 moles of CO₂</em>
F₂ = 15g ₓ (1mol / 38g) = <em>0.39 moles of F₂</em>
<h3>As 15g of Kr contains the less quantity of moles, this sample will con have the lowest pressure</h3>
Answer: True
Explanation: They are formed by the cooling and hardening of molten magma
Because if you change two things then you do not know which one has affected or altered the dependent variable. if you only change one then you know what exactly changed and why
A bond is non polar if it is between same atoms and polar if it is between different atoms.
Same atoms are like two dogs of same strength pulling a bone towards towards each other. But when it’s different atoms it’s like a big dog and small dog then the bone is more towards bigger dog. So it’s the same way in bonds.
Bonds are made up of electrons, when the more stronger pulling atom is present than other the electrons are more towards it and as a result we have polar bond. There is development of a kind of a negative pole and a positive pole.
The stronger atom has electrons towards itself so it has a little more negative charge while the other atom has positive charge. This makes bond polar.
So just look for bond between two different atoms, it would be polar.
Look at the pic below to see the answer.
Marked with green is bond between same atoms... one carbon and another carbon so it is not polar and test marked with blue are polar.
Well the answer should have been 10 but since the bonds at 3 and 8 are two of same type we count only one of them.
The answer is 8... well the answer should be 10 otherwise... discuss it with ur teacher