Explanation:
The balanced equation of the reaction is given as;
Mg(OH)2 (s) + 2 HBr (aq) → MgBr2 (aq) + 2 H2O (l)
1. How many grams of MgBr2 will be produced from 18.3 grams of HBr?
From the reaction;
2 mol of HBr produces 1 mol of MgBr2
Converting to masses using;
Mass = Number of moles * Molar mass
Molar mass of HBr = 80.91 g/mol
Molar mass of MgBr2 = 184.113 g/mol
This means;
(2 * 80.91 = 161.82g) of HBr produces (1 * 184.113 = 184.113g) MgBr2
18.3g would produce x
161.82 = 184.113
18.3 = x
x = (184.113 * 18.3 ) / 161.82 = 20.8 g
2. How many moles of H2O will be produced from 18.3 grams of HBr?
Converting the mass to mol;
Number of moles = Mass / Molar mass = 18.3 / 80.91 = 0.226 mol
From the reaction;
2 mol of HBr produces 2 mol of H2O
0.226 mol would produce x
2 =2
0.226 = x
x = 0.226 * 2 / 2 = 0.226 mol
3. How many grams of Mg(OH)2 are needed to completely react with 18.3 grams of HBr?
From the reaction;
2 mol of HBr reacts with 1 mol of Mg(OH)2
18.3g of HBr = 0.226 mol
2 = 1
0.226 = x
x = 0.226 * 1 /2
x = 0.113 mol
The magnitude of a star as it would appear to a hypothetical observer at a distance of 10 parsecs or 32.6 light-years. This rates how visible celestial bodies are when they are all viewed from the same distance. Luminosity: The brightness of a star in comparison with that of the sun.
Explanation:
<em>When the electron changes levels, it decreases energy and the atom emits photons. The photon is emitted with the electron moving from a higher energy level to a lower energy level. The energy of the photon is the exact energy that is lost by the electron moving to its lower energy level.</em>
Answer:
Anthracite
Explanation:
Anthracite produce highest amount of energy than other. It contain 86-97 percent carbon. Bituminous coal contain 45-86 percent carbon.
Subbituminous cola have 35-45 percent carbon while lignite contain 25-35 percent carbon.
Coal is source of many organic materials. It is fossil fuel and form after long period decay of plants. It is formed when trees are buried under earth
about 500 million years ago. The chemical and bacterial reactions take place and plant wood converted into the peat.
Than because of high temperature and pressure inside the earth peat is converted into the coal.
Through other processes it is than used to make the fuels such as coke. coal tar and coal gas.
Coal tar is the source of many organic compounds which are separated through fractional distillation.
About 80% of coal in Pakistan is used to bake the bricks and also used in lime kilns and for domestic purpose.
