Consider the equation:

4Al + 3O2 = 2Al2O3

Is this equation balanced? Why or why not?

Answer:

Elements in the periodic table are arranged according to the increasing atomic number.

We can predict the chemical properties of an element by looking at it's position in the periodic table.

Answer:

Mole, also spelled mol, in chemistry, a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules, or other

Answer:

Mole, also spelled mol, in chemistry, a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules, or other specified particles.

Explanation:

Explanation:

Given -

molar mass = 135.13 g/mol

To Find -

Solution:

we know that -

So,

Here empirical mass =

12.01 + 1.008 + 14.01 = 27.028

Then,

135.13 = n × 27.028

n = 4.99 ≈ 5

We know that,

Then,

molecular formula = 5(CHN)

= C₅H₅N₅

Therefore,

Option A is correct✔

Answer:

Number of moles = 0.057 × 10⁻⁷  mol

Explanation:

Given data:

Mass of SiO₂ = 3.4 × 10⁻⁷ g

Number of moles = ?

Solution:

Number of moles = mass/molar mass

Molar mass of SiO₂ = 60 g/mol

by putting values,

Number of moles =  3.4 × 10⁻⁷ g / 60 g/mol

Number of moles = 0.057 × 10⁻⁷  mol

Answer:

[tex]\boxed {\boxed {\sf C. \ 4}}[/tex]

Explanation:

First, define some important terms.

We know the mass number is 9. So, the sum of protons and neutrons is 9.

We also know the atoms has 5 neutrons. Therefore, the rest must be protons.

Subtract the 5 neutrons from the overall mass number of 9.

There are 4 protons, so the atomic number is also 4. This atom is beryllium.

Answer:

I also have this question but see the 69 page of ur question book

Answer:

H:H

Explanation:

Answer:

Water from melting snow or rainfall infiltrates into cracks in rocks. ... As this process of freezing and thawing happens repeatedly, the rock begins to weaken and eventually breaks apart into angular fragments.

Explanation:

Water melting from snow or rainfall which infiltrates into cracks in rocks,  this is repeated process of freezing and thawing,  the rock begins to weaken and eventually breaks apart into angular fragments.

A rock can be formed due to the aggregation of mineral constituents in the earth’s crust and  it can be classified is based on different factors like Geological classification, Physical classification, Chemical classification.

Geological classification can be either Sedimentary rock formed by the deposition of sediments by the weathering of pre-existing rocks and it can be carried out by various agents like water, wind, gravity, etc.

Igneous rocks formed  by the  solidification of magma below the earth’s surface which is held together below the earth’s surface and unable to descend, when these magma cools down  and solidifies into igneous rocks.

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The reason why chemists synthesize polymers in the lab is;

because of the need to perform and observe the results of a variety of synthesized polymer reactions and to predict when a reaction will happen.

      Polymers are simply defined as a substance or material made up of long repeating chemical chains of molecules.

     Now, polymer synthesis is simply called polymerization and it is the process by which smaller molecules called monomers undergo covalent bonding to form a longer polymer chain.

      Now, from the definition above, the reason why chemists synthesize polymers in the lab is because of the need to perform and observe the results of a variety of synthesized polymer reactions and to predict when a reaction will happen.

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Answer: The distance is slightly less than 3.5 m

Explanation: assuming wall and target are the same thing, and the bullet has constant velocity, the bullet will travel 7 m in half a second, so half that distance is 3.5 m.

In reality, the bullet is decelerating (at an unknown rate) so the distance is slightly less than 3.5 m.

There is also a vertical velocity component, which means it hits the target/wall at an angle. The trajectory is such that it hits the wall above the shooter because the ricochet hits at ~the level at which it left the firearm.

If the wall was absent, the bullet would have described a parabola which brough it back to the initial level after 7m. This could be calculated, but it means that the actual distance between the shooter and the wall is slightly less than 3.5 m

In addition, the collision with the wall is not 100% elastic, so the velocity aftercthe ricochetvis further reduced.

A calculation would be complex because these confounding factors are not completely independent of each other,  but all reduce the average velocity and therefore the distance.

Therefore it is only possible to say that the distance was somewhat less than 3.5 m

Answer:

Copper

Explanation:

Because copper conducts a lot of electricity, and gets the most electrons

Answer: C. They have fixed ratios between their components.

Answer:

B

Explanation:

by simlfying it you get HCO2

Answer:

A

Explanation:

i had answer it and it was A

Answer: sodium sulfite

Explanation:

Answer:

They run out of fuel

Some heat radiates out

High pressure gases move the piston

Answer:

2 AgCl + Mg(NO3)2 --> 2AgNO3 + MgCl2

Explanation:

This is balanced equation

Answer: Peer-reviewed journal article is the most useful because the information in them had been carefully scrutinized and aproved by people who are experts in that particular field.

Answer:

B

Explanation:

bonding is a process of two different atoms sharing electrons for stability and these electrons are attracted by one atom losing it's electrons to another

Answer:

E.none

Explanation:

because the bonds join with each other and no lone pair is left

Answer:

The element in question here is Scandium, with an atomic number of 21. It is situated in Group 3 and Period 4 of the Periodic Table.

Explanation:

Hope this helped!

Answer: B

We use stoichiometric amounts of P4 and PH3

NO.9) It's actual yield

Answer:

volume of bracelet is 5cm3

mass is 0.0965Kg

Explanation:

1ml = 1cm3

1m3 = 1000000cm3

0.000005m3

Mass = volume*density

19300 Kg/m3 * 0.000005m3 = 0.0965Kg

Answer:

1. 9.45 g

2. 66.9%

Explanation:

The balanced equation for the reaction is given below:

Cu(s) + 4HNO3(aq) —> Cu(NO3)2(aq) + 2NO2(g) + 2 H2O(l)

Next, we shall determine the mass of Cu that reacted and the mass of Cu(NO3)2 produced from the balanced equation. This can be obtained as follow:

Molar mass of Cu = 63.5 g/mol

Mass of Cu from the balanced equation

= 1 × 63.5 = 63.5 g

Molar mass of Cu(NO3)2 = 63.5 + 2[14 + (3×16)]

= 63.5 + 2[14 + 48]

= 63.5 + 2[62]

= 63.5 + 124

= 187.5 g/mol

Mass of Cu(NO3)2 from the balanced equation = 1 × 187.5 = 187.5 g

Summary:

From the balanced equation above,

63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.

1. Determination of the theoretical yield of Cu(NO3)2. This can be obtained as follow:

From the balanced equation above,

63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.

Therefore, 3.20 g of Cu will react to produce = (3.20 × 187.5) / 63.5 = 9.45 g of Cu(NO3)2.

Thus, the theoretical yield of Cu(NO3)2 is 9.45 g.

2. Determination of the percentage yield of Cu(NO3)2.

Actual yield of Cu(NO3)2 = 6.32 g

Theoretical yield of Cu(NO3)2 = 9.45 g.

Percentage of the Cu(NO3)2 =?

Percentage yield = Actual yield /Theoretical yield × 100

Percentage yield of Cu(NO3)2 = 6.32/9.45 × 100

Percentage yield of Cu(NO3)2 = 66.9%

The theoretical yield of Cu(NO₃)₂ is 9.445 g

The percent yield of Cu(NO₃)₂ is 66.91%

From the question.

We are to determine the theoretical yield of Cu(NO₃)₂,

First and foremost, we will write the balanced chemical equation for the reaction properly

The balanced chemical equation for the reaction is

Cu(s) + 4HNO₃(aq) → Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)

This means

1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂, 2 moles of NO₂ and 2 moles of H₂O

To determine the theoretical yield of Cu(NO₃)₂,

First, we will determine the number of moles of Cu that reacted

Mass of Cu = 3.20 g

Molar mass of Cu = 63.546 g/mol

From the formula

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

∴ Number of moles of Cu = [tex]\frac{3.20}{63.546}[/tex]

Number of moles of Cu present = 0.050357 moles

The number of moles of Cu that reacted is 0.050357 moles

Since,

1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂

Then,

0.050357 moles of Cu will react with 0.201428 moles of HNO₃ to produce 0.050357 moles of Cu(NO₃)₂

∴ 0.050357 moles of Cu(NO₃)₂ will be produced during reaction

Now, for the theoretical yield of Cu(NO₃)₂  

From the formula

Mass = Number of moles ×  Molar mass

Molar mass of Cu(NO₃)₂ = 187.56 g/mol

∴ Theoretical yield of Cu(NO₃)₂ = 0.050357 × 187.56

Theoretical yield of Cu(NO₃)₂ = 9.445 g

Hence, the theoretical yield of Cu(NO₃)₂ is 9.445 g

For the percent yield of Cu(NO₃)₂

[tex]Percent \ yield = \frac{Actual \ yield}{Theoretical \ yield } \times 100 \%[/tex]

From the question

Actual yield = 6.32 g

But,

Theoretical yield = 9.445 g

∴ Percent yield of Cu(NO₃)₂ = [tex]\frac{6.32}{9.445} \times 100\%[/tex]

Percent yield of Cu(NO₃)₂ = [tex]\frac{632}{9.445}\%[/tex]

Percent yield of Cu(NO₃)₂ = 66.91%

Hence, the percent yield of Cu(NO₃)₂ is 66.91%

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Answer:

3

2

Explanation:

3O2 => 2O3

the equation is balancing

Answer is

Chloromethane

Explanation: because c stand for carbon an the h stands for hydrogen and ci stands for

Chemical ionization

Initial temperature = -189.4  °C

Given

the volume of a gas is  changed from 3.6 L to 15.5 L

final temperature = 87 °C = 87+ 273 = 360 K

Required

initial temperature

Solution

Charles's Law

When the gas pressure is kept constant, the gas volume is proportional to the temperature  

[tex]\tt \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]

[tex]\tt T_1=\dfrac{V_1.T_2}{V_2}\\\\T_1=\dfrac{3.6\times 360}{15.5}\\\\T_1=83.6~K=-189.4^oC[/tex]

The concentration in mol L-l (M) = 0.717

Given

12% solution of tetrahydrate magnesium chloride (MgCl₂)

Required

The concentration

Solution

Tetrahydrate magnesium chloride (MgCl₂)⇒MgCl₂.4H₂O

MW = Ar Mg+2. Ar Cl+8. Ar H + 4. Ar O

MW=24.31 + 2 x 35.45 + 8 x 1.01 + 4 x 16

MW=24.31+70.9+8.08+64

MW=167.29 g/mol

12% solution = 12 % m/v = 12 g in 100 ml solution

For 1 L solution :

[tex]\tt \dfrac{1}{0.1}\times 12~g=120~g[/tex]

The concentration in g/L = 120 g/L

Convert grams to moles :

[tex]\tt mol=\dfrac{120}{167.29}=0.717[/tex]

Answer: C. Model A shows the three-dimensional shape of the molecule, but Model B does not.

Explanation:

i took the test and it makes the most sence for the modeles.