The number of valence electrons in lithium is 2.
TRUE
FALSE

An empirical shows the simplest ratio among atoms in a compound .

Answer:

I think qs. "A" the net force acting on the book by gravity is down..

The statement is "The net force acting on the book by gravity is down."

Gravity is defined as the force that pulls materials toward the center point of a planet or other entity.

The textbook falls to the ground because of gravitational attraction between the ground and the book.

Because of the Earth's gravitational influence, the textbook moves towards the Earth when nothing is keeping it up. We know that the book has an equivalent impact on the Earth.

With a free fall acceleration of g, the textbook accelerates toward the Earth.

Hence, the correct option is A

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Answer:mass

Explanation:

Answer:

weight is the measure of the force of gravity pulling on the object. mass is the measure of the object's matter.

Answer:

Option D. Decomposition reaction

Explanation:

MgBr₂ (s) —> Mg (s) + Br₂ (l)

To know which option is correct. It is important that we have an understanding of what each option means.

1. Synthesis reaction: This is a type of reaction in which two different elements react to produce a new compound different from the two elements that reacted. e.g

A + D —> AD

2. Combustion reaction: This is a reaction which involves a compound and oxygen to produce carbon dioxide (CO₂) and water (H₂O) e.g methane (CH₄) undergoes combustion reaction as follow:

CH₄+ 2O₂ —> CO₂ + 2H₂O

3. Single Replacement reaction: This is a reaction in which one element replaces or displaces another element in a single compound. This is illustrated below:

X + WZ —> XZ + W

We can see that the X replaces W in the reaction.

4. Decomposition reaction: This is a type of reaction in which a compound decompose or breaks into two or more simple compounds or elements e.g

ZX₄ —> Z + 4X

From the above illustrations, we can conclude that the the reaction:

MgBr₂ (s) —> Mg (s) + Br₂ (l)

Is a decomposition reaction because MgBr₂ breakdown into Mg and Br₂

Answer:

Percent yield = 99.6%

Theoretical yield = 25.5 g

Explanation:

Given data:

Mass of copper = 12.5 g

Mass of copper(II) chloride produced = 25.4 g

Theoretical yield = ?

Percent yield = ?

Solution:

Chemical equation:

Cu + Cl₂       →        CuCl₂

Number of moles of copper:

Number of moles = mass/molar mass

Number of moles = 12.5 g / 63.5 g/mol

Number of moles = 0.19 mol

Now we will compare the moles of copper and copper chloride.

                  Cu          :           CuCl₂

                     1           :               1

                  0.19        :           0.19

Mass of CuCl₂: Theoretical yield

Mass = number of moles × molar mass

Mass = 0.19 mol × 134.45 g/mol

Mass = 25.5 g

Percent yield:

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

Percent yield  = ( 25.4 g/ 25.5 g) ×100

Percent yield = 99.6%

Answer:

The first 5 are exothermic reaction because heat is in product means heat is evolved or given out.

And last no reaction shows that heat is required so last reaction is endothermic reaction.

Explanation:

And heat is evolved in exothermic reaction and heat is absorbed in endo thermic reaction

Answer:

2.94 x 10⁻¹⁴L

Explanation:

To solve this problem, we have to assume that the condition of this water is at standard temperature and pressure, STP.

At STP;

       1 mole of gas have a volume of 22.4L

So, let us find the number of moles of this water first;

         6.02 x 10²³ molecules can be found in 1 mole of a substance

          7.89 x 10⁸ molecules will contain [tex]\frac{7.89 x 10^{8} }{6.02 x 10^{23} }[/tex]   = 1.31 x 10⁻¹⁵mole of water

So;

        Volume of water  = 22.4 x 1.31 x 10⁻¹⁵  = 2.94 x 10⁻¹⁴L

Answer:

[tex]Distance = 40km[/tex]

Explanation:

Given

[tex]Speed = 80km/hr[/tex]

[tex]Time = 0.5hr[/tex]

Required

Determine the distance covered

Distance is calculated as:

[tex]Distance = Speed * Time[/tex]

Substitute values for Speed and Time

[tex]Distance = 80km/hr * 0.5hr[/tex]

[tex]Distance = 80km * 0.5[/tex]

[tex]Distance = 40km[/tex]

Hence, you travelled 40km

Answer:

Explanation:

The reaction expression is given as:

           ⁴⁰₁₈ Ar   →   X  +  ⁰₁B  

To solve this problem, we must bear in mind that both mass number and atomic number must be conserved.

 So;

For the mass number:

               40  = A + 0

                 A  = 40

For atomic number:

                 18  = Z + 1

                  Z = 18 - 1  = 17

An atom is identifiable by the atomic number. Since the atomic number of X is 17 then it is Cl, chlorine

Answer:

Its has a lower density. Think about it, a ship in the water is long because if it wasn't it would have a higher density and sink. The ship needs to diperse its weight across the water to make it less dense.

Explanation:

Your welcome! Have a great day!

Answer:

Each sample has the same number of molecules.

Explanation:

Just took the quiz on edge 2021

Taking into account the definition of Avogadro's number, each sample has the same number of molecules.

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole.

Avogadro's number applies to any substance.

Avogadro's number applies to any substance. This means that the number of molecules in 1 mol of oxygen is equal to the number of molecules in 1 mol of nitrogen.

Finally, the correct answer is the third option: each sample has the same number of molecules.

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Answer:

Explanation:

1st convert given data into % per 100wt...

Total system mass = 63.0g + 5.90g = 68.9g

%Rb = 63.0g/68.9g x 100% = 91.4% per 100wt

%O  =  5.9g / 68.9g x 100% = 8.6%

Then follow the following sequence of calculations...

% => grams => moles => mole ratio => reduce to smallest whole no ratio => empirical ratio => empirical formula

%Rb = 91.4% => 91.4g/ 85.5g·mol⁻¹ =>1.069mole

%O  =   8.6% =>  8.6g/16g·mol⁻¹ => 0.5375mole

Rb:O => 1.069 : 0.5375

Reduce by dividing by the smaller mole value

1.069/0.5375 : 0.5375/0.5375 => 2 : 1 <=> empirical ratio

∴ Empirical Formula => Rb₂O

Answer: [tex]Hg_2^{2+}(aq)+2NO_3^-(aq)+2Na^+(aq)+2Cl^-(aq)\rightarrow Hg_2Cl_2(s)+2Na^+(aq)+2NO_3^-(aq)[/tex]

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.  

A double displacement reaction in which one of the product is formed as a solid is called as precipitation reaction.  

The balanced chemical equation is:

[tex]Hg_2(NO_3)_2(aq)+2NaCl(aq)\rightarrow Hg_2Cl_2(s)+2NaNO_3(aq)[/tex]

The complete ionic equation will be :

[tex]Hg_2^{2+}(aq)+2NO_3^-(aq)+2Na^+(aq)+2Cl^-(aq)\rightarrow Hg_2Cl_2(s)+2Na^+(aq)+2NO_3^-(aq)[/tex]

Answer:

It the acid easier to handel

Answer:

yesyeysesyesyesyesteys

Answer:

90 Minutes

Explanation:

Original concentration = 120 mg

Half life = 30 minutes

Minimum level = 15 mg

Basically, we are to calculate the time it would take to drop from 120 mg to 15 mg.

The half life of a substance is the time it takes for the original concentration of a substance to drop to half it's starting concentration.

First Half life:

Starting concentration = 120mg

Concentration after half life = 120 / 2 = 60 mg

Second Half life;

Starting concentration = 60 mg

Concentration after half life = 60 / 2 = 30 mg

Third Half life;

Starting concentration = 30 mg

Concentration after half life = 30 / 2 = 15 mg

We have reached the minimum 15 mg level. This means it took three half lives to get there.

Total time taken = No of Half lives * Half life duration = 3 * 30 mins = 90 Minutes

Answer:

The moles present in 60 g of calcium are 1.5 moles.

Answer:

In 60 grams there are 1,5 mols

Explanation:

Image 1 shows that the sun is travelling from the left while image 2 shows that the sun is travelling from the right.

We know that the solar system is composed of the sun and the planets. The planets move round the sun in concentric circles and the sun is the focus. This is the heliocentric model of the solar system.

The moon is also a part of the celestial bodies and the light from the moon is dependent on the direction of the movement of the sun. We have to recall that the moon is a non luminous object.

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Answer:

A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.

Explanation:

I hope this helps

Answers are below...and I have answered this question on the basis of above table.

Explanation :-

(a.) Among nonpolar liquids, those with higher molar masses tend to have normal boiling points that are (lower).

(b.) Among compounds of approximately the same molar mass, those with greater polarities tend to have enthalpies of vaporization that are (higher).

(c.) Xe (Xenon), a substance can exist only as a gas at temperatures above its critical temperature. Of the noble gases listed, only Xe has a critical temperature above O°c.

Among nonpolar liquids, those with higher molar masses tend to have normal boiling points that are lower. Among compounds of approximately the same molar mass, those with greater polarities tend to have enthalpies of vaporization that are higher.Xenon can exist only as a gas at temperatures above its critical temperature.

Compound is defined as a chemical substance made up of identical molecules containing atoms from more than one type of chemical element.

Molecule consisting atoms of only one element is not called compound.It is transformed into new substances during chemical reactions. There are four major types of compounds depending on chemical bonding present in them.They are:

1)Molecular compounds where in atoms are joined by covalent bonds.

2) ionic compounds where atoms are joined by ionic bond.

3)Inter-metallic compounds where atoms are held by metallic bonds

4) co-ordination complexes where atoms are held by co-ordinate bonds.

They have a unique chemical structure held together by chemical bonds Compounds have different properties as those of elements because when a compound is formed the properties of the substance are totally altered.

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Answer:

because the particles in solids are more close together and strong so they would support it better than fluid because fluid particles are spread out

Explanation:

Have A Wonderful Day !!

Due to properties of solid substances, they support objects easier than liquid.

Solids can support objects easier than fluids because in solid, particles are present on fix place as compared to liquid which is not fix and can move from one place to another. In Solid substances, particles are fix so they provides better support to the objects which are placed on them.

While on the other hand, in liquid substances particles are mobile so they are not considered better supporter for objects so we can conclude that due to properties of solid substances, they support objects easier than liquid.

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Answer:

NH₄NO₃

Explanation:

In salt naming, the cation is named first, then you must put the name of the anion. In the same way when you are writting the formula. Also, the global charge of a salt is always 0.

Thus, we must write each ion and its charge:

Ammonium: NH₄⁺

Nitrate: NO₃⁻

As both ions have the same charge, the formula is:

The cation first and then the anion.

Answer:

8.2

Explanation:

To solve this problem;

 The concentration of [H⁺]   = 6.8 x 10⁻⁹mol/L

So, we need to convert this to pH:

           pH  = -log [H⁺]

So;

          pH  = -log 6.8 x 10⁻⁹ = 8.2

Answer:

1) The amount is less than one mole, 2) The jar is not completely filled, 3) We have 0.166 moles of sulfur.

Explanation:

We proceed to respond each question below:

1) Is this amount more or less than one mole?

According to the Avogadro's Number, one mole of an element contains about [tex]6.022\times 10^{23}[/tex] atoms. Given that we have [tex]1.000\times 10^{23}[/tex] atoms, then we conclude that this amount is less than one mole.

2) Place the jar underneath the counter. Was the jar completely filled?

Let suppose that the jar can contain up to a mole of sulfur. Then, we conclude that jar is not completely filled.

3) How many moles do you have?

The amount of moles is determined by dividing the current amount of atoms by Avogadro's Number:

[tex]x = \frac{1.000\times 10^{23}\,atoms}{6.022\times 10^{23}\,\frac{atoms}{mole} }[/tex]

[tex]x = \frac{500}{3011}\,mole[/tex]

We have 0.166 moles of sulfur.

Answer:

Explanation:

People use detector to know the ionization of electromagnetic radiation i.e alpha, beta and gamma radiation and the output produced.

In the past, the early detectors use photographic plates which is use to detect tracks due to nuclear reactions.

It is important to know particles before inventing detectors because detectors produces visible trajectories or tracks as a result of particles that are charged which can traverse the apparatus. It was used to detect the positron and also muons and these w are particles that are produced by cosmic rays which is as a result of their interaction in the Earth's atmosphere.

Answer:

No, the student is not correct. The earth may have a lot of water... but not every part of water is drinkable. Most water is filled with bacteria and or viruses making it not suitable to drink! :)

Explanation:

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