18 B 19 C and 20 A
cuz that's it I hope it helps you
Rutherford’s experimental evidence led to the development of this atomic model from the one before it . According to him , a few of the positive particles pointed at a gold foil appeared to ricochet back off of the light metallic foil. This experimental evidence gives the root the development of the atomic model .
Answer:
C-Its product is heavier than each of its reactants.
Explanation:
Correct equation:
¹⁴₇N + ¹₁H → ¹⁵₈O
In the reaction above, we can conclude within the given conditions of the reaction that the product formed is heavier than the reactants.
The product is oxygen with a mass number of 15 as shown by the superscript preceeding the symbol of the atom.
The reactants are:
Nitrogen, N with a mass number of 14
Hydrogen, H with a mass number of 1
The mass number is a true reflection of the mass of an atom. It clearly shows the mass of the nucleons which are the most massive particles that makes up an atom. The nucleons are protons and neutrons that makes up the tiny nucleus of the atom.
Oxygen here has more nucleons that each of Nitrogen and Hydrogen.
Answer:
An increase in entropy
Explanation:
In ice, the molecules are very well ordered because of the H-bonds. As ice melts, the intermolecular forces are broken (requires energy), but the order is interrupted (so entropy increases). Water is more random than ice, so ice spontaneously melts at room temperature.
Just think about this rationally. Melting ice (or anything) will require heat put in (this is called the latent heat of fusion), so you automatically know that the change in enthalpy is going to be positive. In order to make the reaction spontaneous, delta G, the Gibbs free energy has to be negative. So now look at the formula Delta(G) = Delta(H) - T*Delta*(S). If you know that g is negative, and H is positive, then it is only possible if -T*Delta(S) is negative. If that is positive, then Delta(S) has to be positive. So theres your answer :). An increase in entropy
Answer:
The correct option is c) exothermic, negative.
Explanation:
Reactions that releases heat to the surroundings are called exothermic, and are characterized by negative entalpy (ΔH) values.
