It could be a lump of coal.
Since you can break pieces off, maybe charcoal ... the real thing, not a "briquet".
Do your hands get all black when you handle it ?
Answer:
Δ
Explanation:
Hello,
A. In this part, we must include the heat effect for pentane and water:
B. In this part, we just consider the previously computed heat and divide it by the sample of pentane as follows:
Δ
Best regards.
The mantle has a mass of around that is around 68.4% of earth's mass.
So to calculate moles we need to first find out the mass of oxygen and silicon present in mantle. It is given that oxygen is 44.8% by mass in mantle and 21.5% by mass in mantle, therefore to calculate its mass, we need to use
Now, to calculate mass percentage of oxygen
Similarly the mass of silicon can be calculated
Now, the moles of any substance is calculated by
where, mass of oxygen in kilograms is
So,
Similarly
Now, to calculate mole ratio we need to divide every moles to the lowest calculated mole that is the moles of Si and round it off to the nearest whole number.
Answer:
For an element, the molar mass is the mass of 1 mol of atoms of that element; for a covalent molecular compound, it is the mass of 1 mol of molecules of that compound; for an ionic compound, it is the mass of 1 mol of formula units.
Explanation: