Answer:
Isotopes are basically atoms of an element that have an unequal number of neutrons and protons. Of course the proton number remains the same, but the neutron number either decreases or increases, which leads to an overall change in mass. However, no chemical properties of the atom/element are changed as the electrons are the same number and do not react. In regards to Helium 4, the original number of neutrons in Helium is 2, and protons 2 as well. We see an equal number of neutrons and protons, hence an unchanged mass, and the element is <em>not</em> an isotope.
Answer:
being stationary relative to a particular frame of reference or another object; when the position of a body with respect to its surroundings does not change with time it is said to be at rest
Explanation:
Answer:
It is learning about chemical reactions. In chemistry you learn about the elements of the periodic table and how reactive they are.
Explanation:
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Answer:
exothermic entropy is increased
Explanation:
An exothermic process is one whose rate increases when the temperature is decreased. Hence if a decrease in temperature favours the dissolution of more solute at equilibrium, then the process is exothermic.
Similarly, the dissolution of a solute in a solvent increases the disorderliness (entropy) of the system because of the increase in the number of particles present. Hence once a solute in dissolved, the entropy of the system increases.
Answer:
0.0249 moles in 1 g of Ca
Explanation:
Let's think in the molar mass of Ca.
Ca = 40.08 g/mol
So 1 mol weighs 40.08 grams, or in the opposite 40.08 grams is the weigh of 1 mol
The rule of three will be:
40.08 g are contained in 1 mol
1 g may be contained in (1 . 1) / 40.08 = 0.0249 moles
