I got you
The molecular formula for the combustion of butane in oxygen is:
2 C4H10 + 13 O2 ---> 8 CO2 + 10 H20
<span>You take the mass of carbon dioxide, 56.8g, divide by its molar mass, 44.01g/mol, to produce the moles of carbon dioxide. This is multiplied by the molar ratio of butane/CO2, (2/8) = 1/4, which gives the moles of butane required to produce the carbon dioxide. Multiply the number of moles of butane by its molar mass, 58.12g/mol, to produce the mass of butane. Mass of butane = 18.8g</span>
2.50 × 10 ^-5. Move your decimal until you get a whole number. Then count how many times you moved it and that is your exponent. So your exponent is -5 because you're going to the left, if you're going to the right it would be a positive number.
Answer: 12.0 milliliters of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn.
Explanation:
moles =
moles of zinc =
The balanced chemical equation is :

According to stoichiometry:
1 mole of zinc reacts with = 2 moles of HCl
Thus 0.0390 moles of zinc reacts with =
moles of HCl
To calculate the volume for given molarity, we use the equation:
.....(1)
Molarity of
solution = 6.50 M
Volume of solution = ?
Putting values in equation 1, we get:


Thus 12.0 ml of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn
Answer:
∆H= <u>438 KJ/mol</u>
Explanation:
First, we have to find the <u>energy bond values</u> for each compound:
-) Cl-Cl = 243 KJ/mol
-) F-F = 159 KJ/mol
-) F-Cl = 193 KJ/mol
If we check the reaction we can calculate the <u>number of bonds</u>:

In total we will have:
-) Cl-Cl = 1
-) F-F = 3
-) F-Cl = 6
With this in mind. we can calculate the <u>total energy for each bond</u>:
-) Cl-Cl = (1*243 KJ/mol) = 243 KJ/mol
-) F-F = (3*159 KJ/mol) = 477 KJ/mol
-) F-Cl = (6*193 KJ/mol) = 1158 KJ/mol
Now, we can calculate the total energy of the <u>products</u> and the <u>reagents</u>:
Reagents = 243 KJ/mol + 477 KJ/mol = 720 KJ/mol
Products = 1158 KJ/mol
Finally, to calculate the total enthalpy change we have to do a <u>subtraction</u> between products and reagents:
∆H= 1158 KJ/mol-720 KJ/mol = <u>438 KJ/mol</u>
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I hope it helps!
An example would be iodine has a lower relative atomic mass than tellurium, so it should come before tellurium in Mendeleev's table. In order to get iodine in the same group as the other elements with similar properties such as fluorine, chlorine, and bromine, he had to put it after tellurium, which broke his own rules.