M = 4 g = 4/1000 kg = 0.004 kg, θ₂ = 21.0°C, θ₁ = 0°C , c = 0.44kJ/kg°C,
Q = mc(θ₂ - θ₁)
Q = 0.004*0.440*(21 - 0)
Q = 0.03696 kJ
0.03696 kJ<span> of heat is absorbed.</span>
A carbon iota can bond with four other iotas and is just like the four-hole wheel, whereas an oxygen iota, which can bond only to two, is just like the two-hole wheel.
Answer : The mass of the water in two significant figures is, 
Explanation :
In this case the heat given by the hot body is equal to the heat taken by the cold body.
where,
= specific heat of iron metal = 
= specific heat of water = 
= mass of iron metal = 32.3 g
= mass of water = ?
= final temperature of mixture = 
= initial temperature of iron metal = 
= initial temperature of water = 
Now put all the given values in the above formula, we get
Therefore, the mass of the water in two significant figures is,
All the layers should be kept until the experiment is complete.
<h3>What is extraction?</h3>
In chemistry, solvent extraction is accomplished by adding a sample containing the substance to be separated into a system of two solvents, an aqueous layer and an organic layer.
It is important to note that all the layers should be kept until the experiment is complete. No layer ought to be discarded before the work is completed.
Learn more about solvent extraction:brainly.com/question/11041092
the answer of these question is weight
