Answer:
-154KJ/mol
Explanation:
mole of 100ml sample of 0.2M aqueous HCl = Molarity × volume in Liter
= 0.2 × 100 / 1000 ( 1L = 1000 ml) = 0.02 mol and 0.02 mole of HCl solution require 0.02 mole of ammonia according to the mole ratio in the balanced equation.
Heat loss by the reaction = heat gain by calorimeter = mcΔT + 480 J/K
where m is the mass of water = 100g + 100g = 200g since mass of 100ml of water = 100g and it is in both of them and specific heat capacity of water 4.184 J/gK
heat gain by calorimeter = (4.184 × 200 + 480) × 2.34 = 3081.3 J
ΔH per mole = heat loss / number of mole = 3081.3 / 0.02 = 154065.6 = -154KJ/mol
Answer: first option, the work output of the hairdryer will be less than the work input.
Explanation:
1) The work output measured in watts is the power of hair dryer measured in joules per second.
2) The hair dryer converts electrical energy from the wall outlet to mechanical and thermal energy: hot wind.
3) Nevertheless, you can never expect a 100% efficiency of the machines: due to friction, some energy is converted into useless energy.
So, efiiviency = power output / power input< 1 ⇒
power output = work output / time
input power = work input / time
⇒ work output / work input < 1
⇒ work output < work input.
Which is the first option: the work output of the hairdryer will be less than the work input
Answer:
2.71*10^24 formula units in 4.5 moles NaCl
Explanation:
Remark
Make sure you know what a formula unit it. In this case, what it consists of is 1 ion of Na+ Combined with 1 ion of Cl- Together they combine to make NaCl which is ordinary table salt.
1 mole contains 6.02 * 10 ^23 formula units of any chemical -- in this case NaCl.
Therefore 4.50 moles have 4.5 * 6.02*10^23 formula units.
Answer:2.71*10^24
<h3><u>Compare and contrast between bonds and molecules of polar and non-polar:</u></h3>
- Non-polar covalent bonds are a type of covalent bond in which a pair of electrons is shared with each other between two atoms.
- Polar covalent bond is a type of covalent bond in which pair of electrons are not equally shared between two atoms. We can also say bonds are polar when one element in a compound is more electronegative than the other.
- The bond shared in the compound of carbon dioxide between carbon and oxygen atoms is non-polar covalent bond whereas the shared in the compound of water between hydrogen and oxygen atom is polar-covalent bond.
- Polar molecules are those molecules where there is an “electronegativity difference between the bonded atoms”.
- For eg: Water - , Ammonia - , Sulfur dioxide - , Hydrogen sulfide - , Ethanol - , etc.
- Non-polar molecules are those molecules sharing equal electrons between “atoms of a diatomic molecule” or large molecule cancel each other.
- For eg: Carbon dioxide - , Benzene - , Carbon tetrachloride - , Methane - , Ethylene - , etc.