Answer: 
Explanation:
Given
Mass of water in the sample is 
Temperature changes from 
to 
Change in temperature is 
We know, specific heat of water is 
Heat absorbed is given by
Thus, water absorbs of heat from hot plate.
Answer:
The element belongs to group 15 of the present periodic table
Explanation:
Isotopes have the same proton number, what differs is that they have different number of neutrons.
Now since the half-sum of their neutrons is 19, the total number of neutrons would be 19 * 2 = 38 neutrons.
Also, their masses add up to be 68, since the total mass equals sum of neutrons and sum of protons, this means that the total number of protons is 68-38 = 30
Since this is equal in both isotopes, this means that the proton number of the element is 30/2 = 15
The atomic number is the number of protons in the nucleus of an atom. Since the atomic number is 15, this element is phosphorus and it belongs to group 15 of the present periodic table
We'll look at what happens<span> when you </span>dissolve ionic<span> and covalent </span>compounds<span> in </span>water<span>. </span>Ionic compounds<span> break apart into the </span>ions<span> that make them up, a process called dissociation, while covalent </span>compounds only break into the molecules, not the individual atoms.<span>When you immerse an </span>ionic compound<span> in </span>water<span>, the ions are attracted to the </span>water <span>molecules, each of which carries a polar charge. If the attraction between the ions and the </span>water <span>molecules </span>is<span> great enough to break the bonds holding the ions together, the compound </span><span>dissolves</span>
1: The reproduction of an entire unicellular organism.
2: The growth and repair of tissues in multi-cellular animals.
3: The formation of gametes for sexual reproduction in multi-cellular animals.
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