Someone unscramble the first mystery element because I don’t know how to.

-unnecessary comments will be reported

Answer:

a solution color becoming less intense  due to dilution- is not an evidence of a chemical reaction

bubbles (gas formation) - evidence of a chemical reaction

explosion or fire - evidence of a chemical reaction

changes in color- evidence of a chemical reaction

precipitation- evidence of a chemical reaction

changes in temperature - evidence of a chemical reaction

a solid liquifying - is not an evidence of a chemical reaction

solution colors mixing - is not an evidence of a chemical reaction

Explanation:

A chemical change is not easily reversible and yields new substances. It is often accompanied by a loss or gain of heat.

In the answer section, i have shown some evidences that lead us to conclude that a chemical reaction has taken place. The occurrence of a chemical change often goes with the formation of new substances as earlier stated and any of these signs may accompany the process.

For instance, when a metal is dropped in dilute acid solution, bubble of hydrogen gas indicates that a chemical reaction has taken place.

Answer:

Cu    +    2AgNO₃  →   2Ag    +    Cu(NO₃)₂

Explanation:

The reactants are:

         Copper metal  = Cu

         Silver nitrate  = AgNO₃

The products are:

          Silver metal  = Ag

           Copper (II) nitrate  = Cu(NO₃)₂

So, the reaction equation is given as;

      Cu    +    2AgNO₃  →   2Ag    +    Cu(NO₃)₂

This is a single displacement reaction

Answer:C. They can be produced easily in areas with geothermal activity.

D. The land can be used for other purposes while supplying energy.

Explanation:

Both c and d are correct

It is easier to switch to solar and wind energy as compared to other alternative energy sources because they can be produced easily in areas with geothermal activity and can be used for other purposes while supplying energy.

Solar energy is any type of energy generated by the sun. Solar energy can be harnessed directly or indirectly for human use.

Generating energy that produces no greenhouse gas emissions from fossil fuels and reduces some types of air pollution.

Diversifying energy supply and reducing dependence on imported fuels. Creating economic development and jobs in manufacturing, installation, and more.

Hence, options C and D are correct.

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Answer:

How can we make use of acids or bases to remove heavy metals from soils? We can remove heavy metals from soil by adding acid and catching the solution that drains through. Acids can react with metals turning metalic compounds which can be dissolved by water and washed away. Improve crop yields?

Explanation:

A. They are the same

Given

C3H6 and C4H8

Required

The percent compositions

Solution

%C = 3.12/42 x 100% = 85.71%

%H = 6.1/42 x 1005 = 14.29%

C₄H₈(MW=56 g/mol)

%C = 4.12/56 x 100% = 85.71%

%H = 8.1/56 x 100%=14.29%

So they are the same, because mol ratio of C and H in both compounds is the same, 1: 2

Answer:

Explanation:

H₃PO₄ + 3NaOH = Na₃PO₄ + 3 H₂O.

1 mole     3 mole

22.85 mL of the standardized 0.0995M NaOH solution will contain

.0995 x .02285 moles of NaOH

= 22.7357 x 10⁻⁴ moles of NaOH

3 moles of NaOH reacts with 1 mole of H₃PO₄

22.7357 x 10⁻⁴ moles of NaOH reacts with 1 x 22.7357 x 10⁻⁴  / 3 mole of H₃PO₄

= 7.5785 x 10⁻⁴ moles of H₃PO₄

7.5785 x 10⁻⁴ moles of H₃PO₄  is contained in 10 mL or 10⁻² L

molarity of H₃PO₄ solution = 7.5785 x 10⁻⁴ / 10⁻²

= 7.58 x 10⁻² M

= .0758 M .

H2O as an oxidant only

Given

Reaction

2 Na + 2 H2O → 2 NaOH + H2

Required

The function of water in the equation

Solution

Water : oxidizing agent

Na : reducing agent

Na⁰ → Na⁺ (oxidation)

H⁺- → H⁰ (reduction)

Acids and bases according to Bronsted-Lowry

Acid = donor (donor) proton (H⁺ ion)

Base = proton (receiver) acceptor (H⁺ ion)

If water is acting as an acid it should only give 1 H +, so that becomes:

H₂O (l) ⇔ OH⁻ (aq) not H₂

Answer:

yes because of fluorine has higher electronegativity

Answer:

fewest; the same significant figures with; measured numbers.

Explanation:

Without mincing words let us dive straight into the solution to the above question. In order to be able to use the significant figures properly one must know the rules attached to it uses. This is so, because they contributes to the precision of measurements.

When performing multiplication or division calculation, the number of significant figures in the answer[result] will be determined by the one with the smallest number of significant figure in the problem. Therefore, if we have 6.56 which is three[3] significant figures and 1.2 which is two[2] significant figures, then the number of significant figures will be two[2].

6.56 × 1.2= 7.872 = 7.9[ to 2 significant figures].

Answer: Coefficient 0

subscript for V 2

subscript for O 5

Explanation: yes

There is no coefficient in V₂O₅ and the subscript of vanadium V is 2 and the subscript of oxygen is 5.

Vanadium pentoxide is an ionic compound formed by donating electrons from the vanadium metal to oxygen.  The chemical formula of vanadium pentoxide is V₂O₅.

The chemical formula of a compound is written in terms of the chemical symbol of each constituent elements and the number of their atoms. The number of atoms is written as subscript for the chemical symbols.

In V₂O₅, there are are 2 vanadium atoms and 5 oxygen atoms. Coefficients are numbers prior to the formula in reaction. Here there is no coefficient and the subscript for V is 2 and that of O is 5.

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Answer:

B) separation by boiling points

Explanation:

According to the diagram depicted, crude oil is separated into its different units using boiling points.

Answer:

Its particles are evenly distributed.

Explanation:

Solutions are homogenous mixtures of solutes and solvents. In a solution the solute particles are evenly distributed in the solvent.

Here are some characteristics of solutions:

A characteristic of a solution is that its particles are evenly distributed.

A characteristic of a solution is that its particles are evenly distributed. In a solution, the solute (substance being dissolved) is uniformly distributed and mixed with the solvent (the substance doing the dissolving) at the molecular or ionic level.

The particles of the solute become thoroughly dispersed and do not settle out over time. Solutions are generally clear and do not scatter light, unlike suspensions or colloids which may exhibit light scattering due to the presence of larger particles.

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Answer:

A or C

Explanation:

Answer: It is D.

Explanation: Edge 2021

Answer:

Gravitational force between two objects depends on: a. The weight of the objects c. The mass of each object b. The distance between the objects d. Both b and c Please select the best answer from the choices provided A B C D

✓d

The original concentration : 800%

Given

Diluted 1/40

Final concentration 20%

Required

The original concentration

Solution

Dilution is the process of adding solvent to get a more dilute solution.

The moles(n) before and after dilution are the same.

Can be formulated :

 n₁ = n₂

M₁.V₁ = M₂.V₂

diluted 1/40(dilution factor)⇒ V₁/V₂=1/40⇒V₂/V₁=40

M₂ = 0.2(20%)

Input the value for M₁ :

M₁=M₂ x (V₂/V₁)

M₁ = 0.2 x 40

M₂ = 8(800%)

=

Answer:

The manner in which objects will move is determined by the answer to this question. Unbalanced forces will cause objects to change their state of motion

Explanation:

Since these two forces are of equal magnitude and in opposite directions, they balance each other.

Answer:

balance force are those force whose resultant force is zero and unbalanced force are those whose resultant are non zero

Answer:

Incomplete combustion produces carbon monoxide (CO), a toxic gas.

Explanation:

Combustion is the rapid chemical reaction of oxygen in the air or direct oxygen, which is defined as oxidizer, with the different elements that make up the fuel (mainly carbon (C) and hydrogen (H)). These chemical reactions release energy producing local increases in temperature, which causes a flow of heat to the outside.

In other words, on the one hand you have the fuel, which is the substance that oxidizes and that you can find in a solid, liquid or gaseous state and which is made up mostly of carbon and hydrogen.

The oxidizer, for its part, is the substance that oxidizes the fuel, and it is generally the oxygen found in the air.

Certain amounts of oxidizer and fuel must come into contact for combustion to occur.

Incomplete combustion occurs when part of the fuel does not fully react. Incomplete combustion produces carbon monoxide (CO), a toxic gas.

Answer:

Chemical formula of the compound = K₂O

Explanation:

Given:

Number of potassium cation = 2

Number of oxygen anion = 1

Cross valency

Symbol of potassium = k

Symbol of oxygen = o

So;

Chemical formula of the compound = K₂O

Answer:

3

Explanation:

Answer:

So we are given with the mass while we are asked for the amount of volume. So this means, we must need an information on the density. From literature, the density of human fat is 0.918 g/cm³. Convert grams to lb by the conversion that 1,000 g = 2.2 lbs.

Density = 0.918 g/cm³ * (2.2 lbs/1,000 g) = 0.0020196 lb/cm³

Volume = Mass/Density = 12.2 lb / 0.0020196 lb/cm³

Volume = 6,040.8 cm³

Answer: 12.2 moles

Explanation:

7.36x10^24/6.02214076x10^23 = 12.2 moles of free oxygen atoms

Answer:

Na sodium or Rb rubidium

Explanation:

Because Na is present in first group all members of group 1 have 1 electron in valence shell and show similar properties.

Which of the statements about liquids and gases are true?

The particles in liquids and gases can move past one another freely.

Which of the statements about liquids and gases are true?

Both liquids and gases have a definite volume.

The particles in liquids and gases can move past one another freely

Both liquids and gases have a definite shape.

Neither liquids nor gases have a definite shape.

The particles in liquids and gases can move past one another freely.

Answer:

See explanation

Explanation:

Given that;

E = hc/λ

h = 6.63 * 10^-34 Js

c = 3 * 10^8 ms-1

λ = ?

E = 3.978 * 10^-19 J

λ = hc/E

λ = 6.63 * 10^-34 * 3 * 10^8 /3.978 * 10^-19

λ = 19.89 * 10^-26/3.978 * 10^-19

λ = 5 * 10^-7 m The colour is green

2. E = hc/λ

E=  6.63 * 10^-34 * 3 * 10^8 /1000 * 10^-9

E = 1.989 * 10^-19 J

But

E = hf

f = E/h

f =  1.989 * 10^-19/6.63 * 10^-34

f = 3 * 10^14 Hz The radiation is infrared

3. E = hc/λ

λ= hc/E

λ= 6.63 * 10^-34 *  3 * 10^8 /2.0 * 10^-14

λ= 995 * 10^-14 m This is gamma radiation

4. E = hc/λ

E=6.63 * 10^-34 *  3 * 10^8 /620 * 10^-9

E = 3.2 * 10^-19 J

5. E = hf

E= 6.63 * 10^-34 * 2 * 10^17

E = 1326 * 10^-19 J

E = hc/λ

λ= hc/E

λ= 6.63 * 10^-34 * 3 * 10^8 /1326 * 10^-19 = 15 * 10^-9

This is ultraviolet radiation

Answer:

Pressure is often defined as a measure of force applied on an area, or over a unit area.

Explanation:

Answer:

B. Be, Mg, Ca, Sr

Explanation:

Be, Mg, Ca, Sr are parts of the alkaline Earth metal family/group. So they are the second most reactive elements following behind alkali metals. Furthermore, Be, Mg, Ca, Sr all have 2 valence electrons that lose them to form cations. They have low melting points, low boiling points, can conduct electricity, have high malleability and ductility.

Hope it helped!