Answer:
pH = 6.8124
Explanation:
We know pH decreases with increase in temperature.
At room temperature i.e. 25⁰c pH of pure water is equal to 7
We know
Kw = [H⁺][OH⁻]...............(1)
where Kw = water dissociation constant
At equilibrium [H⁺] = [OH⁻]
So at 37⁰c i.e body temperature Kw = 2.4 × 10⁻¹⁴
From equation (1)
[H⁺]² = 2.4 × 10⁻¹⁴
[H⁺] = √2.4 × 10⁻¹⁴
[H⁺] = 1.54 × 10⁻⁷
pH = - log[H⁺]
= - log{1.54 × 10⁻⁷}
= 6.812
Answer: c. Shared equally between two atoms
Electrons are shared equally because the atoms have the same electronegativity.
Answer:
+1
Explanation:
The electrical charge on protons are positive charges.
Protons are subatomic particles and they carry positive charges on them. In all instances, they are found in the tiny nucleus along with neutrons.
Both protons and neutrons contributes the bulk mass of an atom whereas electrons is negligible and inconsequential to the mass of the atom.
- Electrons carry negative charges within an atom with a charge of -1
- Neutrons are uncharged subatomic particles.
- Protons carry positive charges, +1
4. Groups/families: Each column on the periodic table is called a group. Atomic size of atoms in a group increases as you go down the group from top to bottom. Groups contain elements with similarities in their properties such as their charge, number of valence(electrons residing on the outermost electron shell) electrons, and sometimes groups of elements have similar chemical properties as well.
For example, in group 1, with the exception of hydrogen, all the elements are metals. All the elements in group one have only 1 valence electron. These elements tend to form a positive +1 charge because it is easier for them to loose one negative valence electron to another element in order to satisfy the octet rule rather that grab 7 electrons from other elements.
5. Periods tell you: Well, periods are the horizontal rows on the periodic table. There is not much that they are able to tell you other than how many shells of elelctrons the elements in a particular period have.
For example, the first period(consisting of the elements Hydrogen(H) and Helium(He)) Both of those elements only have 1 electron shell. H has 1 electron on its shell and He has 2 electron on its shell. Therefore, helium fills up the very first electron shell because that is the only shell of electron that can be filled by 2 electrons. So, to get to elements with ore than two electrons you must move to the next period. The 2nd period consists of elements with t2 electron shells. Make sense?
6. The Octet Rule: this is a rule that explains why certain elements tend to lose, gain, or share electrons with other elements. Atoms strive to have 8 electrons on their outermost shell of electrons because that is when they are most stable.
For example, the element sodium (Na) likes to "give away" an electron to form an "Ionic bond" with Chlorine (Cl). Chlorine has 7 valence electrons. Therefore, Cl likes to "steal" a negative charge (valence electron) from elements like Na who have only 1 ve- . When Cl "robs" Na, Sodium(Na) becomes a "cation" with a +1 charge (because it got a negative charge stolen). Now, the "cation" Na+1 is happy because it has 8 ve- in its outermost electron shell instead of just 1. Cl is happy because now the "anion" Cl, with a -1 charge(because it grabbed one electron from Na) is happy because Cl-1 has 8 electrons in its outer most shell. This loss and gain of valance electrons in this manner makes table salt(Na-Cl). In order to take or give electrons a bond must be formed between two atoms. This particular bond is called an Ionic bond because it is a bond between a metal(Na) and a non-metal(Cl).
7. An atom the gains one of more electrons will have a __NEGATIVE________ charge. (well, electrons are negatively charged particles. Therefore, when you add them to an atom it gains negative charge as it gains electrons.)
8.An atom that loses one or more electrons will have a _POSITIVE____ charge. ( Well, let's think about it. If i am an atom with a charge of 0 and I lose, give away my negatively charged electrons. I increase in which kind of charge? That's right positive charge!)
9.In an ionic bond each element is left with a ____________ outer shell. ( Let's think about the example I gave for atoms losing and gaining electrons due to the octet rule. When Cl stole Na's valence electron, how many valence elctrons did Cl have? how many did Na+1 end up with? They both ended up with 8 ve- on their outer most shells. So, I would argue the answer for this blank could be "complete".)
10. Atoms __________ one or more electrons with each other to form a covalent bond. ( For this one, it is important to remember what a covalent bond is. A covalent bond is a bond in which electrons are SHARED between elements.)
11. A covalent bond forms between two ____non-metals________. (We already discussed an Ionic bond is formed between a metal and a nonmetal. Covalent bonds on the other hand, occur between two non-metal elements.)
12. An Ionic bond forms between a ____________ and _________. (I just gave you the answer to this question.So, I hope that you can figure this one out on your own.) If you have trouble, and can't find the please comment back and let me know. I will come back and help you out.)
I hope this helped! I tried to be thorough in my explanations. So, that you really understand the material. Fell free to comment back with any and all questions. Hopefully you won't miss any of these questions on the test! Good luck on your test!
