<span>chemical combination of two or more elements in definite proportions. For example, two hydrogen molecules + one oxygen molecule= one water molecule. A solution is a physical combination of two or more chemicals mixed evenly (salt that is dissolved in water). Solutions are also known as homogenous mixtures. A mechanical mixture is a physical combination of two or more chemicals that are not evenly mixed (hot fudge on ice cream). </span>
Answer:

Explanation:
Hello!
In this case, since the ionization of ammonia, which is a weak base, is written as:

We can see that the ammonium ion is the conjugate acid whereas the hydroxide ions the conjugate base; that is why we use the Henderson-Hasselbach equation to compute the pH, given the pKb of ammonia 4.75:
![pH=pKb+log(\frac{[conj\ acid]}{[base]} )](https://tex.z-dn.net/?f=pH%3DpKb%2Blog%28%5Cfrac%7B%5Bconj%5C%20acid%5D%7D%7B%5Bbase%5D%7D%20%29)
In such a way, for the given moles of ammonia, base, and those of ammonium chloride, conjugate acid form, we obtain:

Best regards!
Answer:
First step would be convert to moles
Final Answer: 37.8 g of NaCl
Explanation:
The reaction is:
2Na + Cl₂ → 2NaCI
We convert the mass of each reactant to moles:
18 g . 1mol /23g = 0.783 moles of Na
23g . 1mol / 70.9g = 0.324 moles of chlorine
We use the mole ratio to determine the limiting reactant:
Ratio is 2:1. 2 moles of Na react to 1 mol of chlorine
Then, 0.783 moles of Na, may react to (0.783 . 1)/2 = 0.391 moles.
Excellent!. We need 0.391 moles of Cl₂ and we only have 0.324 moles available. That's why the Cl₂ is our limiting reactant.
We use the mole ratio again, with the product side. (1:2)
1 mol of Cl₂ can produce 2 moles of NaCl
Then, our 0.324 moles of gas, may produce (0.324 . 2)/1 = 0.648 moles
Finally, we convert the moles to grams:
0.648 mol . 58.45g/mol =
Answer:
Average amu is 6.52556
Explanation:
Average the numbers
Add the two masses together.
6.01512+ 7.01600= 13.03112
Then divide by 2, we divide by 2 because that is how many #'s we are given.
13.03112/ 2= 6.52556
Answer:
a) 4869 kj will be released
b) 43.86 g of octane
Explanation:
The heat of combustion is the amount of heat released when one mole of a substance reacts with enough oxygen
since the heat of combustion is per mol of combustible substancewjat we are required to do in this problem is calculate number moles in the reactions although in a different manner
a) MW C3H6O = 158 g/ mol
mol C3H6O = 158 g × 1 mol/ 58.08 g
= 2.72 - 1790 kj / mol ×2.72 mol = 4869 kj
b) Here we are asked the mass of octane to produce 1950 kj of heat knowing that per mole of octane we get 5074.1 kj then
1 mol / 5074.1kj × 1950 kj= 0.384 mol
mass C8H18 = 0.384 mol × 114.23 g/ mol = 43.86 g