Answer:
1. D
2. B
Explanation:
1. Isotopes vary in neutrons. Due to this variance, the difference in neutrons change the mass of the element.
Note: the amount of protons in an element never changes. The number of protons (the atomic number on the periodic table) identifies the element in question. If you add or subtract protons, you change the element.
2. B-10 and B-11 are two isotopes of the element Boron: One with 10 neutrons, and another with 11 neutrons. Because they contain a variance of neutrons, they do not have the same mass. This cancels choices A and D.
The protons of an element are equal to the atomic number of that element. Borons atomic number is 5 (according to the periodic table), so it contains 5 protons. This cancels choice C as the element with 6 protons is Carbon.
Note: The amount of protons in an atom is balanced out by the same amount of electrons to allow for a neutral charge of the element (i.e., the protons, which contain a positive charge, and electrons, which contain a negative charge, cancel each other out. In the case of Boron: +5 protons - 5 electrons = 0 charge). This is why choice B is correct, as the consideration of an ion is not necessary for this question.
Answer:
The United States is the global leader in food waste, with Americans discarding nearly 40 million tons of food every year. That's 80 billion pounds of food and equates to more than $161 billion², approximately 219 pounds³ of waste per person and 30-40 percent4 of the US food supply.
The curved movement of air or water is the result of which of these:
The answer is B
The balanced reaction is
Ca + 2H2O → Ca(OH)2 + H2
Here this reaction can be compared with
A + BC ---> AB + C
So here one reactant (A) is accepting a group which is being given by another compound (BC) however the A is not giving any group / element or ion
So this single displacement
Similarly in the given reaction
the anion OH- is only being replaced
The element Ca accepts OH- and H2O loses the same group to form new element H2
So the correct answer is
Single replacement also known as single displacement
