All categories

3 years ago

What percent of magnesium bromide, MgBr2, is magnesium?

1 answer:

7 0

First, we need to calculate the molar mass of the whole compound by adding the masses of each atom from the periodic table.

Mg= 24.3 g/mol
Br= 80.0 g/mol

molar mass MgBr2= 24.3 + 2 x 80.0= 184.3 g/mol

to find the percent of magnesium doing "parts over the whole"
the mass of magnesium over the total mass. then times 100 because it is a percentage value

24.3/184.3x 100= 13.2%

You might be interested in

Boron has an average mass of 10.81. One isotope of boron has a mass of 10.012938 and a relative abundance of 19.80 percent. The

Andrej [43]

The average mass of an atom is calculated with the formula:

average mass = abundance of isotope (1) × mass of isotope (1) + abundance of isotope (2) × mass of isotope (2) + ... an so on

For the boron we have two isotopes, so the formula will become:

average mass of boron = abundance of isotope (1) × mass of isotope (1) + abundance of isotope (2) × mass of isotope (2)

We plug in the values:

10.81 = 0.1980 × 10.012938 + 0.8020 × mass of isotope (2)

10.81 = 1.98 + 0.8020 × mass of isotope (2)

10.81 - 1.98 = 0.8020 × mass of isotope (2)

8.83 = 0.8020 × mass of isotope (2)

mass of isotope (2) = 8.83 / 0.8020

mass of isotope (2) = 11.009975

mass of isotope (1) = 10.012938 (given by the question)

5 0

3 years ago

Explain why energy sources do not have 100% efficiency. Why do you think some have lower efficiencies?

bearhunter [10]

Answer:

Energy sources do not have 100% efficiency because the processes of energy conversion to usable forms involves energy losses.

Some have lower efficiencies due to; energy losses in form of heat during conversion, poor technology applied during conversion of energy and lack of desire equipment to use in the energy conversion system.

Explanation:

The desired form of energy for use is derived from conversion of energy from the source using an energy converter into another form which is usable. The efficiency of the energy converter is calculated as;

л = output energy/input energy

The efficiency of energy is limited to the cost of equipment required for conversion from energy source by the energy converter to a form which is usable. Additionally, because energy sources are scarce, the technology to use in energy conversion is a factor affecting energy efficiency in that high efficiency will require advanced technology with better equipment leading higher costs of that energy form. when heat losses are involved during energy conversion, efficiency lowers, thus its better if such losses are used as energy input in another system.

5 0

3 years ago

The side chains of amino acids may contain..

salantis [7]

The correct answer is d)all of above

examples for a are tyrosine for b lysine and for c isoleucine

6 0

3 years ago

Read 2 more answers

Which element would most likely be a shiny solid at room temperature and a good conductor of electricity?

Alborosie

Answer:

Explanation:

rest are nonmetals and they are not shiny

7 0

3 years ago

What mass, in grams, of NaNo, is needed to make 6.24 Liters of a 0.500 M solution?

mafiozo [28]

Answer:

that hared ldkdjjjdjjdjdjj

3 0

3 years ago