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3 years ago

4. What animal resources from other continents benefited South Americans?

1 answer:

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South America's major mineral resources are gold, silver, copper, iron ore, tin, and petroleum. These resources found in South America have brought high income to its countries especially in times of war or of rapid economic growth by industrialized countries elsewhere.

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3. Two people are playing tug of war. One person pulls to the right with 32 N of force. The other person pulls to the left with

SVETLANKA909090 [29]

The net force = -5 N

The direction : to the left(negative sign)

<h3>Further explanation </h3>

Net force : the sum of all forces acting on an object

Force is a vector quantity that has both magnitude and direction,

We agree that the move up and to the right is a positive sign, while down and to the left is a negative sign.

The direction of the force (horizontal motion) is to the right (+32 N), and to the left (-37 N), so the net force :

$\tt \sum F=F~right-F~left\\\\\sum F=32-37\\\\\sum F=-5~N$

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3 years ago

Rank the following elements by effective nuclear charge, Zeff, for a valence electron. F LI Be B N

Stels [109]

Answer:

Rank in increasing order of effective nuclear charge:

Li < Be < B < N < F

Explanation:

This explains the meaning of effective nuclear charge, Zeff, how to determine it, and the calculations for a valence electron of each of the five given elements: F, Li, Be, B, and N.

1) Effective nuclear charge definitions

While the total positive charge of the atom nucleus (Z) is equal to the number of protons, the electrons farther away from the nucleus experience an effective nuclear charge (Zeff) less than the total nuclear charge, due to the fact that electrons in between the nucleus and the outer electrons partially cancel the atraction from the nucleus.

Such effect on on a valence electron is estimated as the atomic number less the number of electrons closer to the nucleus than the electron whose effective nuclear charge is being determined: Zeff = Z - S.

2) Z eff for a F valence electron:

F's atomic number: Z = 9
Total number of electrons: 9 (same numer of protons)
Period: 17 (search in the periodic table or do the electron configuration)
Number of valence electrons: 7 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 9 - 7 = 2
Zeff = Z - S = 9 - 2 = 7

3) Z eff for a Li valence eletron:

Li's atomic number: Z = 3
Total number of electrons: 3 (same number of protons)
Period: 1 (search on the periodic table or do the electron configuration)
Number of valence electrons: 1 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 3 - 1 = 2
Z eff = Z - S = 3 - 2 = 1.

4) Z eff for a Be valence eletron:

Be's atomic number: Z = 4
Total number of electrons: 4 (same number of protons)
Period: 2 (search on the periodic table or do the electron configuration)
Number of valence electrons: 2 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 4 - 2 = 2
Z eff = Z - S = 4 - 2 = 2

5) Z eff for a B valence eletron:

B's atomic number: Z = 5
Total number of electrons: 5 (same number of protons)
Period: 13 (search on the periodic table or do the electron configuration)
Number of valence electrons: 3 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 5 - 3 = 2
Z eff = Z - S = 5 - 2 = 3

6) Z eff for a N valence eletron:

N's atomic number: Z = 7
Total number of electrons: 7 (same number of protons)
Period: 15 (search on the periodic table or do the electron configuration)
Number of valence electrons: 5 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 7 - 5 = 2
Z eff = Z - S = 7 - 2 = 5

7) Summary (order):

Atom Zeff for a valence electron

Li 1

Be 2

Conclusion: the order is Li < Be < B < N < F

6 0

3 years ago

How many atoms of phosphorus are in 3.80 mol of copper(II) phosphate?

Sladkaya [172]

Wouldn't you take Avogadro' number and multiply by 3.80 maybe

6 0

3 years ago

Someone help me with chemistry on my account/page please :))

Gemiola [76]

Answer:

Explanation:

5 0

2 years ago

Someone please help! I will give Brainliest to who answers the best! Write an explanation of how mass determines (or affects) th

xxTIMURxx [149]

Gravity is the force of motion pulling down objects to the ground. If there was no gravity, everyone would walking as if they were on the moon.

Mass is what gravity needs. If an object has a little amount of mass, gravity will be able to easily bring it to the ground.

If an object has a very huge amount of mass, gravity will still be able to bring it to the ground but it will be hard.

For example: An airplane has a HUGE amount of mass. Gravity pulls it down but the airplane needs to be steering up in order for it to be straight. Gravity is applied on the airplane when it is landing.

BUT..... if a table is in the way of an object it depends if it will fall down to the ground or stay on the table.

If an object has little mass and a table is in the way of gravity pulling it down to the ground, the object will stay on the table. Like a plate of food on a table.

If an object has a very big amount of mass and a table is in the way of gravity pulling it to the ground, the object will break the object and make it's make to the ground. That is mostly why most of the time people have very strong tables/ anything to hold a heavy object.

Another example is if you're lifting weights and you have little amount of mass, you're most likely to get the little sized weight. It depend on you mass.

Here are some pictures I included here as well of Mass and gravity.

Glad to help! :) :D

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3 years ago