Answer: D.
Explanation:
Le Chatelier's Principle states that when a Chemical reaction in equilibrium experiences some change, whether that's a temperature change, a pressure change, or a concentration change, the equilibrium will shift to annul the effect of that change.
Answer:
I'm pretty sure it's 15 electrons. Hope this helps :).
Explanation:
*Note: there seems to be a "typo" in the given problem. The "1000" must probably be "100" only since summing up the total number of atoms given for the different isotopes would not equal 1000 but 100 instead. Using 1000 as the basis for the mass fractions would give an answer which is 10 times less than should be.
To determine the average atomic mass of halfnium, the mass fractions of the isotopes multiplied by their respected atomic masses must all be added.
1. Determining the mass fractions (m1, m2...m5) with 100 atoms total as the basis:
m1 = 5/100 = 0.05
m2 = 19/100 = 0.19
m3 = 27/100 = 0.27
m4 = 14/100 = 0.14
m5 = 35/100 = 0.35
2. Multiplying the mass fractions with the atomic masses of the respective isotopes.
Average atomic mass of Halfnium
= (m1*176) + (m2*177) + (m3*178) + (m4*179) + (m5*180)
= (0.05*176) + (0.19*177) + (0.27*178) + (0.14*179) + (0.35*180)
= 178.55 amu
Thus, the average atomic mass of Halfnium based on the given data for its isotopes is 178.55 amu.
Answer:
II and IV.
Explanation:
I. (INCORRECT). A model is a tentative to determinate a thing that can't be proved, and it's made based on evidence. If the model can explain the observation in nature, it is considered right, although it can be proved by a theory.
II. (CORRECT). The most accepted model of atoms says that they're formed by tiny particles, protons, neutrons, and electrons, with the first two on the nucleus, and the other surrounding it in an open space.
III. (INCORRECT). A heterogeneous mixture is a mixture of substances that is possible to identify phases of them, such as in oil and water. In the air, isn't possible to identify the constituents, and it's a homogeneous mixture.
IV. (CORRECT). Silver has atomic number 47, which is its number of protons. The atomic mass is the sum of protons and neutrons, so the number of neutrons is 108 - 47 = 61.