Answer:
Explanation:
1 mole of any substance contains the same number of particles. The particles can vary (atoms, molecules, formula units), but there are always 6.022*10²³ particles. In this case, the particles are formula units of potassium nitrate or KNO₃.
Let's create a ratio.
Since we are trying to find the formula units in 0.250 moles, we multiply by that number.
The units of moles of potassium nitrate cancel.
The denominator of 1 can be ignored, so we can make a simple multiplication problem.
If we round to the nearest tenth, the 0 in the hundredth place tells us to leave the 5 in the tenth place.
0.250 moles of potassium nitrate is approximately equal to 1.5*10²³ formula units of potassium nitrate and choice B is correct.
Answer:
C2H5O
Explanation:
In a 100 g sample we would have
53.31 g of C
11.18g of H
35.51g of O
First, we find the relative number of atoms of each element by dividing the number of grams the element has in the compound by its atomic mass.
Atomic mass of carbon is 12.011
Relative number of carbon atoms = 53.31 / 12.011 = 4.4
Atomic mass of hydrogen = 1.007
Relative number of hydrogen atoms : 11.18/1.007 = 11.1
Atomic mass of oxygen : 15.999
Relative number of oxygen atoms : 35.51 / 15.999 = 2.2
Now we find a ratio of the relative number of atoms by dividing the # of relative atoms of each element by the element's relative number of atoms that had the lowest number. ( oxygen which had 2.2 ) The outcome of each will be the subscript or number of atoms of each element.
Carbon : 4.4 / 2.2 = 2
Hydrogen : 11.1 / 2.2 = 5
Oxygen : 2.2 / 2.2 = 1
The answer is C2H5O
Answer:
2. 14
Explanation:
To form Br₂ bond, a total of 14 electrons are needed.
Bromine is an element in the 7th group on the periodic table. It has 7 valence electrons.
- In forming the bromine gas, the two atoms of bromine shares 7 electrons each.
- These electrons are from their outermost shell.
- The outermost shell is the valence shell.
- So, two atoms donating 7 electrons gives 14 electrons.
Answer:
A.
Explanation:
A redox reaction is a reaction when oxidation states (or numbers) change during reaction.
<u>Answer:</u> The element represented by M is Strontium.
<u>Explanation:</u>
Let us consider the molar mass of metal be 'x'.
The molar mass of MO will be = Molar mass of oxygen + Molar mass of metal = (16 + x)g/mol
It is given in the question that 15.44% of oxygen is present in metal oxide. So, the equation becomes:
The metal atom having molar mass as 87.62/mol is Strontium.
Hence, the element represented by M is Strontium.
