Read the hypothesis below. Hypothesis: if a steel surface is wet with water, then the friction will be reduced, which question best matches the hypothesis ???

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.

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 %

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Answer:

a- 5.616

b- Oxygen

c- hydrogen

d- 4.68 extra

e- 74.47%

I hope this helps! Cheers ^^

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.

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.

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Answer:

34.6g

Explanation:

Given parameters:

Mass of Octane  = 11.2g

  Reaction expression;

      2C₈H₁₈  + 25O₂  →  16CO₂  + 18H₂O

Mass of octane = 11.2g

Unknown:

Mass of carbon dioxide produced  = ?

Solution:

From the balanced reaction equation;

         2 mole of octane produced 16 moles of carbon dioxide

From the given specie, let us find the number of moles;

    Number of moles  = [tex]\frac{mass}{molar mass}[/tex]  

 Molar mass of C₈H₁₈   = 8(12) + 18(1) = 114g/mole

Number of moles of octane  = [tex]\frac{11.2}{114}[/tex]   = 0.098mole

    2 mole of octane produced 16 moles of carbon dioxide

    0.098 mole of octane will produce [tex]\frac{0.098 x 16}{2}[/tex]   = 0.79mole of CO₂

Mass of CO₂ = number of moles x molar mass

           Molar mass of CO₂ = 12 + 2(16)  = 44g/mol

Mass of CO₂  = 0.79 x 44  = 34.6g

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:

Answer:

volume

Explanation:

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

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.

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.

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.

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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:

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

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

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

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.

Answer:

c i just took the test

Explanation:

Answer:

The correct option is Malachite which has both copper nd oxygen.

Explanation:

As we the symbol of copper is Cu while the symbols of oxygen is O. As the chemical formula of malachite is Cu₂CO₃(OH)₂. So it has Cu as well as O.

Glucose has only oxygen but no copper

Chalcopyrite has copper but no oxygen

Calcite has oxygen but no copper.

So correct answer is only malachite.

pls give brainlist

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.

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

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.

Answer:

0.6

Explanation:

Answer:

A.

Explanation:

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.

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!

Answer:

Aluminum

Explanation:

Answer:

????? questions there no question

Answer:

what

Explanation:

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

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

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.

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Answer:

C

Explanation:

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.

Answer:

B

Explanation:

D=S×T

=120km/h×4hrs

=480km

Answer:

the answer is b

Explanation:

this is the answer :)

Answer:

2.09 moles

Explanation:

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

Answer:

Acid

Explanation:

acid

Answer:

An acid

Explanation:

H2OSO4 is Sulfuric Acid