I need help plz Its a simple middle school question on science about energy PLZZZ I need help

I Need Help Plz Its A Simple Middle School Question On Science About Energy PLZZZ I Need Help

Answers

Answer 1

Answer:

I believe C

Explanation:

The absence of air between the two forms a vacuum seal which preserves the contents inside. I think that's right... good luck :)

Answer 2
It is C. Ive seen this question before

Related Questions

how many atoms are there in a 1 mol sample of water

Answers

Answer:

Explanation:

1 molecule has 2 hydrogens and 1 oxygen. That's 3 atoms.

1 mol of anything is 6.02 * 10^23 items. There are 3 atoms in 1 molecule

There are 6.02*10^23 * 3 atoms in a mol of water

Answer: 1.804 * 10^24 atoms in a mol of water.

A sample of 5.0 g of hydrogen gas reacts with 5.0 g of oxygen gas.
2H2(g) + O2(g) > 2H2O

Please answer the questions in a b c d and e, or at least in any of the ones you know. Thank you.

Answers

The percent yield of the reaction has been 74.47%.

The balanced chemical equation for the reaction has been:

[tex]\rm 2\;H_2\;+\;O_2\;\rightarrow\;2\;H_2O[/tex]

(a) The theoretical yield can be calculated as:

The theoretical yield of water has been:

1 mole of oxygen produces = 2 moles of water

0.1562 moles of oxygen produces = 0.1562 [tex]\times[/tex] 2

= 0.312 moles of water.

The mass of water has been = moles [tex]\times[/tex] molecular weight

The theoretical yield of water = 0.312 [tex]\times[/tex] 18 grams

The theoretical yield of water = 5.616 grams.

(b) The limiting reactant has been the one whose concentration has been in a lesser quantity for the complete utilization of other reactants.

According to the reaction, for the complete utilization of 2 moles of Hydrogen, 1 mole of oxygen has been used.

The moles of 5 grams Hydrogen:

Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]

Moles of hydrogen = [tex]\rm \dfrac{5}{1}[/tex]

Moles of hydrogen = 5 mol.

Moles of Oxygen = [tex]\rm \dfrac{5}{32}[/tex]

Moles of oxygen = 0.1562 mol.

For the complete utilization of 5 moles of hydrogen 2.5 moles of oxygen has been required.

Since the oxygen has been present in a lesser quantity, the oxygen has been the limiting reactant.

(c) The consumption of 0.1562 moles of Oxygen has required 0.312 mol of Hydrogen. The hydrogen has been present in a higher quantity than required.

Thus. hydrogen has been the excess reactant.

(d) The remained excess reactant has been:

Remained = Total - consumed

Remained = 5 - 0.312

Remained = 4.68 mol.

The excess reactant has been 4.68 mol extra than required.

(e) The theoretical yield of water has been:

1 mole of oxygen produces = 2 moles of water

0.1562 moles of oxygen produces = 0.1562 [tex]\times[/tex] 2

= 0.312 moles of water.

The mass of water has been = moles [tex]\times[/tex] molecular weight

The theoretical yield of water = 0.312 [tex]\times[/tex] 18 grams

The theoretical yield of water = 5.616 grams.

The actual yield of water has been 4.2 grams.

The percent yield of water = [tex]\rm \dfrac{Actual\;yield}{Theoretical\;yield}\;\times\;100[/tex]

The percent yield of water = [tex]\rm \dfrac{4.2}{5.616}\;\times\;100[/tex]

The percent yield of water = 74.74 %

For more information about the limiting reactant, refer to the link:

https://brainly.com/question/14225536

Answer:

a- 5.616

b- Oxygen

c- hydrogen

d- 4.68 extra

e- 74.47%

I hope this helps! Cheers ^^

What factors do you think should be considered in selecting a metal to use to reclaim copper? Which factor do you think is the most important? Explain.

Answers

Answer:

Aluminum

Explanation:

Aluminum would be the best choice to reuse  copper from the copper chloride solution because it  In the aluminum–copper reaction, the chloride ions help remove the aluminum oxide coating so that a reaction can take place through the oxidation of aluminum and the reduction of copper ions.The aluminum–copper chloride reaction is a simplified version of a waste reclamation and reduction strategy for handling toxic-waste materials.

What is the difference between the chemical symbols CI and Cl2?

Answers

Cl refer to chlorine atoms. They don't exist naturally in that form. Rather, Cl2 refer to chlorine molecules, and they exist as that form in nature.

When heated, calcium carbonate decomposes according to the equation given below:

CaCO3 --> CaO + CO2
If 50.0 g of CaCO3 react but only 20.0 g of CO2 are recovered, what is the percent yield of this reaction?


90.9%
40.0%
66.7%
250%

Answers

Answer:

Percent yield = 90.9%

Explanation:

Given data:

Mass of CaCO₃ = 50.0 g

Mass of CO₂ produced = 20.0 g

Percent yield = ?

Solution:

Chemical equation:

CaCO₃ →  CaO + CO₂

Number of moles of CaCO₃:

Number of moles = mass/molar mass

Number of moles = 50.0 g/ 100.1 g/mol

Number of moles = 0.5 mol

Now we will compare the moles of CO₂ with CaCO₃.

                      CaCO₃          :        CO₂

                          1                :           1

                       0.5               :          0.5

Mass of CO₂: Theoretical yield

Mass = number of moles × molar mass

Mass = 0.5 mol × 44 g/mol

Mass = 22 g

Percent yield:

Percent yield = ( actual yield / theoretical yield ) × 100

Percent yield = (20.0 g/ 22.0 g) × 100

Percent yield = 0.909 × 100

Percent yield = 90.9%

A 2.0 sample of N2 occupy 50.0L at 15 degrees Celsius and 640mmHg. What volume will the gas occupy at 45 degrees Celsius and 160mmHg?

Answers

Answer:

220.8L

Explanation:

Given parameters:

Initial volume  = 50L

Initial temperature = 15°C  = 288K

Initial pressure = 640mmHg

Final temperature  = 45°C  = 318K

Final pressure  = 160mmHg

Unknown:

Final volume  = ?

Solution:

Using the combined law;

        [tex]\frac{p_{1}v_{1} }{T_{1} }[/tex]  = [tex]\frac{p_{2}v_{2} }{T_{2} }[/tex]  

p,v and T are pressure, volume and Temperature

    [tex]\frac{640 x 50}{288}[/tex]  = [tex]\frac{160 x v_{2} }{318}[/tex]

     160 x 288 x v₂ = 640 x 50 x 318

                         v₂ = 220.8L

HELP!!

H2SO4 is _____.

a base
an acid
a neutral

(The 2 is small and so is 4)

Answers

Answer:

Acid

Explanation:

acid

Answer:

An acid

Explanation:

H2OSO4 is Sulfuric Acid

When water is solid, do molecules move?

Answers

Answer:

Ice is water in its solid form. Ice keeps its shape, even if it's removed from the container. The molecules in ice are locked into place and cannot move or slide past one another, but they do vibrate a little bit.

Explanation:

As the temperature drops or decreases, the water molecules gradually slow down. Eventually they stop moving and simply vibrate back and forth. At this point ice is formed, the solid phase of water. If the temperature is allowed to increase, the molecules will once again begin to vibrate faster and faster.

Answer:Ice is water in its solid form. Ice keeps its shape, even if it's removed from the container. The molecules in ice are locked into place and cannot move or slide past one another, but they do vibrate a little bit.

Explanation:

In order for photosynthesis to take place, energy in the form of ______ is required.

A. Sound

B. Light

C. Electricity

D. Kinetic

Answers

B. Light
Chloroplasts on leaves absorb the sunlight to make energy which is what causes photosynthesis. Hope this helps!

Melting chocolate (a change of state) is an example of a

Answers

It is an example of a physical change because the chocolate changes from a solid to a liquid however it’s chemical composition is not changed so it’s a physical change.

What is a scientific model? How is a scientific model helpful to the brain for relaying a scientific
concept?

Answers

Answer: A scientific model is a physical and mathematical and conceptual representation of a system of ideas, events or processes.

ANd also for your second question i dont know what you mean?

Explanation:

Scientists work to recognize and comprehend patterns in our world by applying their scientific expertise to provide predictions about the patterns.

What is the main purpose of scientific model?

In a range of scientific specialties, from chemistry and physics to biology and the Earth sciences, research models are employed to explain and forecast the behavior of real things or systems. The ability to depict things that are too little or enormous, explain either past or present, and forecast the future are all advantages of employing model beyond nature.

Why are scientific models important?

Models can help you visualize something is difficult to see or understand. Models can help in scientific predictions, process comprehension, and concept communication. Because it frequently includes a variety of hypotheses or facts, an evolutionary theory varies from other general explanations. A science simulation may be used to verify a scientific theory or to demonstrate a scientific model.

To know more about Scientific model visit:

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I have similar chemical and physical properties to calcium but my molecular mass is lower, what element am I?
-Potassium
-Scandium
-Magnesium
-Strontium

Answers

Potassium is the answer

In the reaction 2Li(s) + 2H2O(I) -> 2LiOH(aq) + H2(g), which compound is in the aqueous state?

A. Li

B. H2O

C. LiOH

B. H2

Answers

The substance that is in aqueous state in the reaction is LiOH from the equation shown.

What is an aqueous state?

An aqueous state is a state in which a substance is dissolved in water. This implies that the substance is in solution.

Thus, the substance that is in aqueous state in the reaction is LiOH from the equation shown.

Learn more about aqueous state:https://brainly.com/question/14959096

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Answer:

C

Explanation:

Over 30 species of dinosaur fossils with feathers have been discovered. Therefore, birds evolved from dinosaurs.

A.) Claim
B.) Evidence
C.) Reasoning

Answers

The awnser is C because if it was a claim it would be proven with facts and if it were evidence it would also be proven with facts

HELP AND ILL PUT U ON BRAINLIEST ! -THANKS

Answers

Answer:

2Fe₂O₃

Explanation:

If the number of atoms of each element are the same on reactant and product sides, it is a balanced equation. This is not a balanced equation because the number of atoms of each element are not the same on reactant and product sides.

To balance an equation, let's first list the atoms:

FeO

Then, we count the number of atoms on both sides:

1 Fe 22 O 3

We multiply the number of atoms for each element on either side by the number of molecules (aka coefficient, or "big number"):

4 Fe 26 O 3

To balance the equation, we need the total number for Fe on the right side to be 4, and the total number for O on the right side to be 6. We can do that by adding a "big number", or coefficient in front, which when multiplied by the number of atoms for each element, makes a balanced equation.

2 is a good value: 2 × 2 = 4, and 2 × 3 = 6.

As such:

4Fe + 3O₂ → 2Fe₂O₃

HELP ME PLEASE!!

Density (D) is defined by mass/volume .

Which item increases as heat is applied?

D
m
V

Answers

Answer:

volume

Explanation:

things expand when heat is applied taking up more space hence volume

Is this true Bc I’m not sure

Answers

Answer:

????? questions there no question

Answer:

what

Explanation:

Make the following conversion.

60 dkm = _____ km

6,000
0.060
60,000
0.60

Answers

Answer:

0.6

Explanation:

Compare the elements: Sn, Sb, Te, and I:
Which has the lowest ionization energy?
Why?

Answers

Answer:

Sn

Explanation:

Tin, Sn, will have the lowest ionization energy from the given choices.

  Sn is an element is the fourth group on the periodic table.

Ionization energy is a measure of the readiness of an atom to lose an electron. The lower the value, the easier it is for an atom to want to lose an electron and vice versa.

Across a period, I.E increases progressively from left to right due to the decreasing atomic radii caused by the increasing nuclear charge which is not compensated for by successive electronic shells.

       Sn, Sb, Te and I are all in the 5th period.

what is the gel-like part of the eye?

Answers

Answer:

vitreous

Explination:

The vitreous is the gel-like fluid that fills your eye. It's full of tiny fibers that attach to your retina (the light-sensitive layer of tissue at the back of the eye). As you get older, the fibers of your vitreous pull away from the retina.

Answer:

The vitreous

Explanation:

Mark & Sally were in lab and they were working on a chemical reactions experiment. They mixed 2 liquids together and a white sold color appeared. What can Mark & Sally conclude as their observation?

A chemical change
B physical change

Answers

Answer:

A chemical change

Explanation:

From the observation, a chemical change has ensued.

A chemical change is one in which new kind of matter is formed. It is always accompanied by energy changes . This process is not easily reversible.

This process depicted by Mark and Sally is chemical change. This reaction is a precipitation reaction since an insoluble solid has been formed. In chemical changes the process is not reversible.

What describes using organisms that were only alive during a specific time period to estimate the unknown age of items

A radioactive dating
B law of superposition
C relative dating
D index fossil

Answers

Answer:

c i just took the test

Explanation:

If you have 1.26 x 1024 molecules, how many moles do you have?

Answers

Answer:

2.09 moles

Explanation:

1 mole=6.022*10^23 moles --> 1.26×10^(24)/(6.022*10^23)=2.09 moles

Please help me with this question. What are two elements that will react similarly to beryllium ?

Answers

Probably the two elements with properties most like beryllium are magnesium and aluminum.

According to the electronic configuration elements that will react similarly to beryllium  are magnesium and calcium.

What is electronic configuration?

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.

Learn more about electronic configuration,here:

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Metal oxides are in which state?

Answers

Answer:

Metal oxides are crystalline solids that contain a metal cation and an oxide anion. They typically react with water to form bases or with acids to form salts.

Explanation:

Hope this helps!

1.How far can you travel if you drive 4 hours and can average 120 Km/hr?
a.30 Km
b.480 Km
c.80 Km

Answers

Answer:

B

Explanation:

D=S×T

=120km/h×4hrs

=480km

Answer:

the answer is b

Explanation:

this is the answer :)

A cylinder at left with balls evenly spaced throughout the cylinder with an arrow leading to a cylinder at right with balls stacked near the bottom of the cylinder.
Which change of state is shown in the model?

condensation
deposition
boiling
freezing

Answers

Answer:

condensation

Explanation:

The state of change shown in the diagram is a condensation process. During condensation, heat is removed from vapor or gases and then they aggregate back to the liquid state.

The image to the left is that of a typical gas molecule. To the right we have a liquid where the particles have aggregated In going from a gas to liquid, the phase change is a condensation reaction. This is a form of physical change.

Answer:

Use these images to identify each state of matter.

A cylinder at left labeled A contains balls widely separated in space. A cylinder in the center labeled B contains balls stacked near the bottom of the cylinder. A cylinder at right labeled C contains balls in a layer along the bottom of the cylinder.

Match each image with the correct state of matter.

 

A:  

gas

B:  

solid

C:  

liquid

Explanation: i got it right trust me

Out of magnesium, iron, calcium, mercury, copper, or aluminum which metal would be the most useful when transporting acids or water solutions? PLEASE HELP!!! Thank you

Answers

May be mercury is the best choice because it would not react with acid

Will give 50 points, If a decrease in temperature accompanies a reaction, what occurred?


Energy was released.


Energy was destroyed.


Energy was created.


Energy was absorbed.

Answers

Answer:

A.

Explanation:

Answer: Energy is Being absorbed

The melting point of table salt is 801.Is this a physical or chemical property

Answers

Physical property
Physical properties include density, harness, color, melting and boiling points

Answer:

Physical

Explanation:

When something melts it is still the same substance.

For example:

Ice and water are still both water, so that would be a physical change.

If a reaction changes the substance into a new/different substance then it is a chemical change.

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