<span>Answer : B. hope it helped</span>
igneous rocks cool very slowly
Explanation:
Large crystals are formed when rocks cool very slowly. This gives time for crystallization nuclei to form and other crystals aggregates round it.
- Large crystals in rocks are typical of intrusive igneous rocks.
- These rocks are formed beneath the earth surface and they usually have big crystals.
- This because they cool slowly and have time for crystal formation.
- Rocks that cools rapidly are extrusive igneous rocks.
- They are usually fine grained and glassy in nature.
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Answer:
The heat required to raise the temperature of 12g of water from 16 C to 21 C is 60 cal.
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
There is a direct proportional relationship between heat and temperature. The constant of proportionality depends on the substance that constitutes the body as on its mass, and is the product of the specific heat by the mass of the body. So, the equation that allows calculating heat exchanges is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case, you know:
- Q=?
- c= 4.186

- m= 12 g
- ΔT=Tfinal - Tinitial= 21 °C - 16°C= 5 °C
Replacing:
Q= 4.186
*12 g *5 °C
Solving:
Q=251.16 J
Since 1 J is equal to 0.2388 cal, then the following rule of three can be applied: if 1 J is equal to 0.2388 cal, then 251.16 J to how many cal are?

cal= 59.98 ≅ 60
<u><em>The heat required to raise the temperature of 12g of water from 16 C to 21 C is 60 cal.</em></u>
First you need to find the mass of one mole of the element. (say Fe)
Find Fe on the periodic table, it should tell you what the average atomic mass is.
The average atomic mass = mass of one mole.(in this case it is 55.85g)
Take your moles (1.35mol Fe) and multiply it by the mass of one mole (55.85g)
1.35mol*55.85g/mol=75.39g
(Just repeat that method for the other problems) use the formula <span><span>moles=<span><span>mass</span><span>Molar mass
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