Answer:
Empirical formula: BH3
Molecular Formula: B2H6
Explanation:
To solve the exercise, we need to know how many boron atoms and how many hydrogen atoms the compound has. We know that of the total weight of the compound, 78.14% correspond to boron and 21.86% to hydrogen. As the weight of the compound is between 27 g and 28 g, using the above percentages we can solve that the compound has between 21.1 g and 21.8 g of boron, and between 5.9 g and 6.1 g of hydrogen:
100% _____ 27 g
78.14% _____ x = 78.14% * 27g / 100% = 21.1 g boron
100% ______27 g
21.86% ______ x = 21.86% * 27g / 100% = 5.9 g hydrogen
100% _____ 28 g
78.14% _____ x = 78.14% * 28g / 100% = 21.8 g boron
100% _____ 28g
21.86% _____ x = 21.86% * 28g / 100% = 6.1 g hydrogen
So, if the atomic weight of boron is 10.8 g, there must be two boron atoms in the compound that sum 21.6 g. The weight of hydrogen is 1 g, so the compound must have six hydrogen atoms.
The molecular formula represents the real amount of atoms that form a compound. Therefore, the molecular formula of the compound is B2H6.
The empirical formula is the minimum expression that represents the proportion of atoms in a compound. For example, ethane has 2 carbon atoms and 6 hydrogen atoms, so its molecular formula is C2H6, however, its empirical formula is CH3. Therefore, the empirical formula of the boron compound is BH3.
Answer:
Its in the Explanation
Explanation:
Here's what I got.
Aluminium-27 is an isotope of aluminium characterized by the fact that is has a mass number equal to
27
.
Now, an atom's mass number tells you the total number of protons and of neutrons that atom has in its nucleus. Since you're dealing with an isotope of aluminum, it follows that this atom must have the exact same number of protons in its nucleus.
The number of protons an atom has in its nucleus is given by the atomic number. A quick looks in the periodic table will show that aluminum has an atomic number equal to
13
.
This means that any atom that is an isotope of aluminum will have
13
protons in its nucleus.
Since you're dealing with a neutral atom, the number of electrons that surround the nucleus must be equal to the number of protons found in the nucleus.
Therefore, the aluminium-27 isotope will have
13
electrons surrounding its nucleus.
Finally, use the known mass number to determine how many neutrons you have
mass number
=
no. of protons
+
no. of neutrons
no. of neutrons
=
27
−
13
=
14
Your welcome :)
Answer : The number of grams of solute in 500.0 mL of 0.189 M KOH is, 5.292 grams
Solution : Given,
Volume of solution = 500 ml
Molarity of KOH solution = 0.189 M
Molar mass of KOH = 56 g/mole
Formula used :
Now put all the given values in this formula, we get the mass of solute KOH.
Therefore, the number of grams of solute in 500.0 mL of 0.189 M KOH is, 5.292 grams
Answer:
His map of the ocean floor did not support his theory
Explanation:
- Alfred Wegner was a great scientist
- He observed the plate tectonics of earth and described it in a theory.
- It was dismissed after viewing his ocean floor
