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Blababa [14]
2 years ago
7

Black holes cannot be seen. However scientists think that black holes exist because of their effect on surrounding matter. Descr

ibe another force or phenomenon that cannot be seen directly. Give examples of the effects of this force on everyday objects.
BTW this is not the right subject but there is no astronomy category so I am using this subject.
Chemistry
2 answers:
san4es73 [151]2 years ago
5 0

Answer:

l

Explanation:

l

lara31 [8.8K]2 years ago
4 0

Answer:

If Black Holes Are "Black," How Do Scientists Know They Are There? A black hole can not be seen because strong gravity pulls all of the light into the middle of the black hole. But scientists can see how the strong gravity affects the stars and gas around the black hole.

Explanation:

some examples; 1. Pushing a wheel barrow.

2. Opening or closing a door.

3. Squeezing wet clothes.

4. Gravitational force.

5. Brakes applied to stop a moving vehicle.

6. A football kicked harder that decreases due to the frictional force.

7. Rubbing a glass rod with a silk.

8. Pressure applied on a pin of a notice board.

9. Running

10. Pushing

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Who uses holmium? I need to know for a science project.
Tanzania [10]

Answer:

Holmium can absorb neutrons, so it is used in nuclear reactors to keep a chain reaction under control. Its alloys are used in some magnets. Holmium has no known biological role, and is non-toxic. Holmium is found as a minor component of the minerals monazite and bastnaesite.

Explanation:

this is basically used in industries

7 0
3 years ago
Ions can have a positive or negative charge. false or true
Fudgin [204]
True. Ions can have a positive or negative charge.
7 0
3 years ago
Read 2 more answers
Helpp
Alexeev081 [22]
The answer is D. Liquid to Solid
3 0
3 years ago
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For the following reaction, 5.04 grams of nitrogen gas are allowed to react with 8.98 grams of oxygen gas: nitrogen(g) + oxygen(
OLga [1]

Answer:

1. 10.8 g of NO

2. N₂ is the limting reagent

3. 3.2 g of O₂ does not react

Explanation:

We determine the reaction: N₂(g) + O₂(g) →  2NO(g)

We need to determine the limiting reactant, but first we need the moles of each:

5.04 g / 29 g/mol = 0.180 moles N₂

8.98 g / 32 g/mol = 0.280 moles O₂

Ratio is 1:1, so the limiting reactant is the N₂. For 0.280 moles of O₂ I need the same amount, but I only have 0.180 moles of N₂

Ratio is 1:2. 1 mol of N₂ can produce 2 moles of NO

Then, 0.180 moles of N₂ may produce (0.180 .2) / 1 =  0.360 moles NO

If we convert them to mass → 0.360 mol . 30 g/1 mol = 10.8 g

As ratio is 1:1, for 0.180 moles of N₂, I need 0.180 moles of O₂.

As I have 0.280 moles of O₂, (0.280 - 0.180 ) = 0.100 moles does not react.

0.1 moles . 32 g/mol = 3.2 g of O₂ remains after the reaction is complete.

8 0
3 years ago
Read 2 more answers
HELP PLEASE
Tatiana [17]

Answer:

Samira's model correctly demonstrates how the properties changed with the rearrangement of the atoms. However not all atoms are accounted for. There is a missing reactant.

Explanation:

Samira's model correctly demonstrated how the atoms in two compounds reacted to form two new products. However, the elements present in the reactants side should be the elements that make up the new products in the product side. But as the diagram shows, Sameera has mistakenly added a new element to one of her products which will be wrong.

7 0
3 years ago
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