Answer number 15 to get 20 points

Answers

Answer 1

Answer: corundum because it is hard and glassy

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When silver coins are found in ancient shipwrecks,they are coated with a black crust. What question could you ask to help you decide whether the silver underwent a chemical change or a physical change? Explain.
What happens when you mix acid and base?
What experiment did j.j. thomson do ?
Name one Importance of solar power
Could a mixture be made up of only elements and no compounds? explain.

What makes up soil besides rock particles,minerals,air,and water?

Answers

decayed organic material

Aaron is visiting a national park in Pennsylvania. The ranger tells Aaron that he is unlikely to see any groundhogs because it is winter.Which of the following is the most likely reason Aaron would NOT see any groundhogs?

The groundhogs are hibernating.

The groundhogs migrated.

The groundhogs have died out.

The groundhogs are gathering food.

Answers

Answer:

The groundhogs are hibernating.

Explanation:

Groundhogs hibernate during the winter months and don't come out of their burrows.

The groundhogs are hibernating, during winter

One balloon was only partly filled when put on the plane. During the flight, the balloon volumeincreased from 7 L at 1.0 atm to 9 L. What was the cabin pressure on the airplane during the flight?
(Assume the balloon stretched very easily and the temperature was constant.)

Answers

Answer:

P₂ = 0.8 atm

Explanation:

Given data:

Initial pressure = 1 atm

Initial volume = 7 L

Final volume = 9 L

Final pressure = ?

Solution:

P₁V₁ = P₂V₂

P₁ = Initial pressure

V₁ = Initial volume

P₂ = Final pressure

V₂ = Final volume

Now we will put the vales in formula.

P₁V₁ = P₂V₂

P₂ = P₁V₁ /V₂

P₂ = 1 atm × 7 L / 9 L

P₂ = 7 atm. L / 9 L

P₂ = 0.8 atm

Zinc has the chemical symbol Zn and the atomic number 30. How many protons, neutrons, and electrons does an atom of zinc-69 have?A. 30 protons, 39, neutrons, 39 neutrons
B. 39 protons, 30 neutrons, 30 neutrons
C. 39 protons, 30 neutrons, 39 electrons
D. 30 protons, 39, neutrons, 30 electrons

Answers

Answer:

D. 30 protons, 39 neutrons, 30 electrons

Explanation:

The atomic number (Z) is the number of protons (p) in the nucleus. Since

Z = 30, p = 30.

In a neutral atom, the number of electrons (e) equals the number of protons. Since p = 30, e = 30.

The mass number (A) is the number of protons plus the number of neutrons (n).

A = p + n

For an atom of zinc-69,

69 = 30 + n Subtract 30 from each side and transpose

n = 39

Zinc has the chemical symbol Zn and the atomic number 30. D. 30 protons, 39, neutrons, 30 electrons

What is Zinc

Zinc has the chemical symbol Zn, and its atomic number is 30. This means that every atom of zinc contains 30 protons in its nucleus.

An atom of zinc-69 (Zn-69) is one that contains:

- 30 protons (since zinc has an atomic number of 30).

- 39 neutrons (subtract the atomic number from the mass number: 69 - 30 = 39).

- 30 electrons (in a neutral atom, the number of electrons is equal to the number of protons).

So, the correct option is option d 30 protons, 39 neutrons, 30 electrons.

Learn more about Zinc from

brainly.com/question/31013398

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GIVE ONE ADVANTAGE AND ONE DISADVANTAGE OF RECYCLING THE MATERIALS FROM THIS TYPE OF BALLPOINT PEN

Answers

The advantage is that you will be able to re-use that ballpoint pen in another manner. It could be a toy and such. The only disadvantage that it is really hard to transform the parts of the ball pen especially it has ink and the like. You can't recycle the ink for another purpose.

Which Idea was once accepted is now considered a scientifically inaccurate A.tge nucleus is the center of the atom
b.an atom is solid material
c.electrons have a negative charge
d.electrons are arranged in layers

Answers

Well, the nucleus is the center, the electrons are negative and arranged in layers, so atoms are not necessarily solid (you know, liquids, gases and plasma is made of atoms too -- plasma from ions, true)

Answer:

The answer is A

Explanation:

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