Explanation:
Hardness of rocks makes weathering difficult and not easy to come by.
Weathering is the physical disintegration and chemical decomposition of rocks to form sediment and soils.
The agents of weathering are primarily the agents of denudation which are wind, rainfall, glacier, gravity and temperature.
- Most igneous and metamorphic rocks are usually termed hard rocks.
- Sedimentary rocks typically falls into the category of soft rocks.
- Hard rocks are more compact and have their crystals woven into one another.
- It takes a longer time for them to get weathered.
- Soft rocks are often times bounded by cements.
- The cements are chemical substances that easily reacts and can cause they to be easily broken down.
Therefore, the harder a rock is, the more time it takes for it to be disintegrated.
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Answer:
40%
Explanation:
We'll begin by obtaining the molar mass of MgO. This is illustrated below:
Molar Mass of MgO = 24 + 16 = 40g/mol
Observing the formula MgO, we have 1 atom of O in it.
The percentage composition by mass of oxygen in MgO is given by:
Mass of O/Molar Mass of MgO x 100
= 16/40 x 100 = 40%
Answer:
2ErF3 +3Mg = 3MgF2 + 2Er
Explanation:
This is a single replacement equation where there are 2 metals. The bonds are broken and new bonds are formed again by Mg and F.
Er has a +3 charge and F has a -1 charge. You switch it around and you get ErF3. Then you add the second reactant, Mg. The product is MgF as stated, and Mg has a charge of +2 and F has -1. You switch it again and you get MgF2. Then the second product Er is there.
Now we have
ErF3+Mg=MgF2+Er
So we balance the equation because of the law of conservation of mass.
Make F equal, so we add the coefficents 2 and 3
2ErF3+Mg=3MgF2+Er
And now Mg and Er need balancing so
2ErF3+3Mg=3MgF2+2Er
Hope this helped
