Water
Water is a compound because it is made from more than one kind of element (oxygen and hydrogen).
Answer:
(a) when both the liquid are mixed, they become completely miscible as the intermolecular forces between them are equal to the intra molecular forces
(b) since the magnitude of intermolecular force = intra molecular forces, Delta H solution=0
(c) Delta H solute = positive
Delta H solvent = positive
Delta H mix = negative
Explanation:
Answer:
maybe the 3rd stance if your not sure try to search in googel
<span>Barium - A) Great conductor of heat and electricity
Potassium - B) Malleable and highly reactive
Boron - C) Has properties of both metals and nonmetals
Neon - D) Nonreactive gas
Let's look at each element and it's place on the periodic chart to see what matches.
Potassium - This is on the far left column for alkali metals. This means it's highly reactive and since it's a metal, it's both malleable and conductive. Looking at the available options, "B) Malleable and highly reactive" is the best choice.
Barium - This element is in the second column from the left, so it's a fairly reactive metal, but not nearly as reactive as Potassium above. So "A) Great conductor of heat and electricity" is the best choice here, although I wouldn't call it "great". The resistivity of barium is about 20 times larger than copper.
Boron - This element is about in the middle of the periodic chart, so it does have the properties of both metals and nonmetals. So "C) Has properties of both metals and nonmetals" is the best choice.
Neon - This is in the far right column for noble gasses. Very non-reactive. So "D) Nonreactive gas" is the best choice.</span>
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.




