Calculate the molar mass of aluminum oxide (Al2O3). Express your answer to four significant figures.

The molar mass of Al2O3 is

Answer:

A.

Explanation:

The amount of mass always stays the same, matter cannot be created nor destroyed, it can only change forms. Thus, the answer is A.  

In a chemical reaction the total mass of all the substances taking part in the reaction remains the same. Also, the number of atoms in a reaction remains the same. Mass cannot be created or destroyed in a chemical reaction.

I hope this helps..

Answer:OD. Producing light

Explanation:

Answer:

electronic configuration of Y is 1s²2s²2p⁶3s²3px²3py²3pz¹

Explanation:

The electronic structure of chlorine is 1s²2s²2p⁶3s²3px²3py²3pz¹. The first two electrons are coming from pairs in the 3p levels and are therefore rather easier to remove than if they were unpaired

Answer:

The correct option is;

Produces wind currents

Explanation:

The Earth's atmosphere which comprises the gases surrounding the Earth when heated up by the heating effect of the Sun creates winds such as land and sea breezes

The kind of forces that produce land and sea breezes results in wind patterns globally that affect climate. The curving masses of air due to the rotation of the Earth results in coriolis effect and trade winds that determines the cyclic (annual) seasons and weather.

Answer: A

Explanation:

Produces wind currents

Answer:

Explanation:

To calculate the number of atoms we must first calculate the number of moles

Molar mass = mass / number of moles

number of moles = mass / Molar mass

Molar mass (K) = 39.10mole

mass = 2.10g

number of moles = 2.10/ 39.10

= 0.0537mol

After that we use the formula

N = n × L

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10^23 entities

Number of K atoms is

N = 0.0537 × 6.02 × 10^13

Hope this helps you.

Answer:

Hope this helps you

Answer:

C. If Assertion is true statement but Reason is false.

Explanation:

The burning of magnesium in air produces magnesium oxide as shown by the equation;

2Mg(s) + O2(g) -----> 2MgO(s)

The magnesium oxide solid is recovered as a white ash. This is a typical example of an oxidation reaction which is also a combustion reaction.

The reason has nothing at all to do with the assertion hence the answer given.

Magnesium oxide is basic just like the oxides of other metals and dissolves in water to yield an alkali.

Answer:

Answer:

C. If Assertion is true statement but Reason is false.

Explanation:

The burning of magnesium in air produces magnesium oxide as shown by the equation;

2Mg(s) + O2(g) -----> 2MgO(s)

The magnesium oxide solid is recovered as a white ash. This is a typical example of an oxidation reaction which is also a combustion reaction.

The reason has nothing at all to do with the assertion hence the answer given.

Magnesium oxide is basic just like the oxides of other metals and dissolves in water to yield an alkali.

Explanation:

Answer:

5.13g of H2O.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

HBr(aq) + NaOH(aq) —> NaBr(aq) + H2O(l)

Next, we shall determine the masses of HBr and NaOH that reacted and the mass of H2O produced from the balanced equation.

This is illustrated below:

Molar mass of HBr = 1 + 80 = = 81g/mol

Mass of HBr from the balanced equation = 1 x 81 = 81g

Molar mass of NaOH = 23 + 16 + 1 = 40g/mol

Mass of NaOH from the balanced equation = 1 x 40 = 40g

Molar mass of H2O = (2x1) + 16 = 18g/mol

Mass of H2O from the balanced equation = 1 x 18 = 18g

Thus, from the balanced equation above,

81g of HBr reacted with 40g of NaOH to produce 18g of H2O.

Next, we shall determine the limiting reactant. This is illustrated below:

From the balanced equation above,

81g of HBr reacted with 40g of NaOH.

Therefore, 34g of HBr will react with = (34 x 40)/81 = 16.79g of NaOH.

From the calculations made above, we can see that it will take a higher mass (i.e 16.79g) of NaOH than what was given (i.e 11.4g) to react completely with 34g of HBr.

Therefore, NaOH is the limiting reactant and HBr is the excess react.

Finally, we can determine the maximum mass of H2O produced as shown below.

In this case the limiting reactant will used because it will produce the maximum mass of H2O since all of it is consumed in the reaction.

The limiting reactant is NaOH and the maximum mass of H2O produced can be obtained as follow:

From the balanced equation above,

40g of NaOH reacted to produce 18g of H2O.

Therefore, 11.4g of NaOH will react to produce = (11.4 x 18)/40 = 5.13g of H2O.

Therefore, the maximum mass of H2O produced from the reaction is 5.13g.

Answer:

1.89g of HNO3

Explanation:

Data obtained from the question include:

Mass of water = 31.5 g

Molality of HNO3 = 0.950 m

Mass of HNO3 =.?

Next, we shall determine the number of mole of HNO3 in the solution.

Mass of water = 31.5 g = 31.5/1000 = 0.0315 Kg

Molality of HNO3 = 0.950 m

Number of mole of HNO3 =..?

Molality is simply defined as the mole of solute per unit kilogram of solvent (water) i.e

Molality = mole /kg of water

With the above formula, the mole of HNO3 can be obtained as follow:

Molality = mole /kg of water

0.950 = mole of HNO3 /0.0315

Cross multiply

Mole of HNO3 = 0.950 x 0.0315

Mole of HNO3 = 0.03 mole

Finally, we shall convert 0.03 mole of HNO3 to grams. This is illustrated below:

Molar mass of HNO3 = 1 + 14 + (16x3) = 63g/mol

Mole of HNO3 = 0.03 mole

Mass of HNO3 =..?

Mole = mass /molar mass

0.03 = mass of HNO3 /63

Cross multiply

Mass of HNO3 = 0.03 x 63

Mass of HNO3 = 1.89g

Therefore, 1.89g of HNO3 is needed to prepare the solution.

Answer:

Explanation:

The initial chemical energy is 50 J. The arrow for heat is the widest output arrow. The arrow for chemical energy is the shortest output arrow.

Answer:

photosynthesis maybe

Explanation:

bare with me i may be wrong or i may be right it's been a while since i've been in a chem classroom. so basically during photosynthesis a plant is taking the energy from the sun, H2O, and CO2, this ends up being like 6CO2 + 6H20 + (energy), and it converts this energy to glucose (→ C6H12O6 + 6O2 ) so the energy is never used up in this process it is merely changed. i don't really know but i hope it at least helps some

Answer:

Kc = [CaO] [O2] / [CaCO3]

Explanation:

Equilibrium constant, Kc is simply defined as the ratio of the concentration of products raised to their coefficient to the concentration of the reactants raised to their coefficient.

Thus, we can write the equation for the equilibrium constant, Kc for the reaction given in the question above as follow:

CaCO3(s) <==> CaO(s) + O2(g)

Kc = [CaO] [O2] / [CaCO3]

Answer:

when we drink the milk the digestive system produce protease enzyme to break down the protein of milk.

Answer:

Protons = 89

Neutrons = 142

Electrons = 89

Option C

Explanation:

Hello,

Were required to find the proton, neutron and electron of an element Y

The atomic mass of element Y is composed of the protons and neutrons while the atomic number is the exact amount of protons present in the element.

Element = ₈₉²³¹Y

Atomic number = 89

Number of protons = 89

Number of electrons = 89

Atomic mass = 231

Atomic mass = protons + neutrons

231 = 89 + neutrons

Neutrons = 231 - 89

Neutrons = 142

Therefore the number of protons is 89, number of neutrons is 142 and number of electrons is 89.

Note: for an electrically neutral atom, the number of protons must be equal to the number of electrons

Answer:

Diagram B shows the correct arrangement of electrons in the product.

Magnesium reacts with fluorine to form magnesium fluoride two electrons of magnesium are transferred to the 2 atoms of fluorine and fluorine is the most electronegative element of the periodic table. Option C is correct.

Electronegativity is the tendency or power of an atom to attract the electrons from the metals they are mostly nonmetals and want to complete their octave too.

The most electronegative elements of the periodic table are oxygen, nitrogen, and fluorine, as they are always willing to complete the octave, and fluorine will take electrons from magnesium.

Therefore, Option C is correct if the 2 atoms of fluorine and fluorine are the most electronegative element of the periodic table. Magnesium reacts with fluorine to form magnesium fluoride two electrons of magnesium are transferred.

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Answer:

You should get the catalyst back already.

Explanation:

A catalyst shouldn't be used up during a chemical reaction. It is used to speed up a reaction, but it shouldn't disappear/be used up by a chemical reaction.

Answer:

The essence including its given problem is outlined in the following segment on the context..

Explanation:

The given values are:

Moles of CO₂,

x = 0.01962

Moles of water,

[tex]\frac{y}{2} =0.01961[/tex]

[tex]y=2\times 0.01961[/tex]

  [tex]=0.03922[/tex]

Compound's mass,

= 0.4647 g

Let the compound's formula will be:

[tex]C_{x}H_{y}O_{z}[/tex]

Combustion's general equation will be:

⇒  [tex]C_{x}H_{y}O_{z}+x+(\frac{y}{4}-\frac{z}{2}) O_{2}=xCO_{2}+\frac{y}{2H_{2}O}[/tex]

On putting the estimated values, we get

⇒  [tex]12\times x=1\times y+16\times z=0.4647[/tex]

⇒  [tex]12\times 0.01962+1\times 0.03922+16\times z=0.4647[/tex]

⇒  [tex]0.27466+16z=0.4647[/tex]

⇒                     [tex]z=0.01187[/tex]

Now,

x : y : z = [tex]0.01962:0.03922:0.01187[/tex]

           = [tex]\frac{0.01962}{0.0118}:\frac{0.03922}{0.0188}:\frac{0.0188}{0.0188}[/tex]

           = [tex]1.6:3.3:1.0[/tex]

           = [tex]3:6:2[/tex]

So that the empirical formula seems to be "C₃H₆O₂".

Answer:

4.1/  [tex]\frac{41}{10}[/tex]

Explanation

Do the calculation carefully because this calculation has negative term.

I hope you will understand.

3/8 + 7/2 + (-3/5) + 9/8 + (-3/2) + 6/5​

31/5+(-3/5)+(-3/2)

41/10

4.1

Answer:

2Na + Cl2 ------> 2NaCl

sodium + chlorine = sodium chloride (salt)

Answer:

Sodium chloride NaCl

Explanation:

NaCl will form.

2Na + Cl2 ----> 2NaCl

Each Na atom donates 1 electron from its outermost shell electron to each chlroine atom, so that Na can attain full outermost shell electrons (octet), where it is most stable. Na+ ion is formed after losing 1 electron.

Each chlroine atom gains 1 electron so that it can have 8 outermost shell electrons (stable). It becomes Cl- ion.

Combining Na+ and Cl-, NaCl is formed so that the net charge is 0. To balance the equation, since chlorine exists as diatomic molecule, 2 Na atom reacts with 1 chlorine molecule (2 chlorine atoms) to form 2 NaCl.

Answer:

Read below

Explanation:

The effects of London dispersion forces are most obvious in systems that are very non-polar (e.g., that lack ionic bonds), such as hydrocarbons and highly symmetric molecules such as bromine (Br2, a liquid at room temperature), iodine (I2, a solid at room temperature).

Answer:

2+

Explanation:

Apex lolz

Answer:

What are the periodic trends of ionic radii? Check all that apply.

*Ionic radii tend to increase down a group.

Ionic radii tend to decrease across a period.

Anionic radii tend to increase across a period.

*Cationic radii tend to decrease across a period.

*Ionic radii increase when switching from cations to anions in a period.

Answer:

- Ionic Radii Tend To Increase Down A Group.

- Cationic Radii Tend To Decrease Across A Period.

- Ionic Radii Increase When Switching From Cations To Anions In A Period.

Explanation:

i got it correct on edge

The organelle that is matched correctly is the Cell Wall

The cell wall functions as a protective organelle as well as gives shape to the cell.

The cell wall is an organelle found in prokaryotic cells and plant cells.

Cell walls generally function to protect the cell by delimiting its surroundings the membrane from damage.

They also act as permeable structures to substances as well as give the respective cells their characteristic shapes.

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Answer:

Where are the answer choices

?

Answer:

The enthalpy is increased by the increased heat of the reaction.

Explanation:

In this reaction, as the transition from solid to liquid state, enthalpy increases, that is, the heat applied to change its state is greater and this increases, reaching a mayor disorder.

If the reaction increases its heat, and a liquid state passes, the enthalpy increases, therefore the disorder also and the entropy will also be increased.

Answer:

The gas cloud must be very dense.Temperatures must exceed 14 million Kelvin

Nuclear fusion is the process in which atomic nuclei come together to form heavier nuclei, releasing large amounts of energy in the process. The correct statements are The gas cloud must be very dense, Atoms must be stripped of their electrons, and Temperatures must exceed 14 million Kelvin.

For fusion to occur, certain conditions must be met. The gas cloud or plasma must be dense enough to allow for a sufficient number of collisions between atomic nuclei. Gravitational attraction, on the other hand, is necessary to bring the atomic nuclei close enough together for the strong nuclear force to overcome the electrostatic repulsion between positively charged nuclei.

Atoms must be stripped of their electrons because, in a plasma state, the atoms are ionized, meaning they have lost or gained electrons and exist as charged particles.

Hence, the correct statements are The gas cloud must be very dense, Atoms must be stripped of their electrons, and Temperatures must exceed 14 million Kelvin.

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Answer:

A. 257600g (i.e 257.6 Kg) of CaO were produced.

B. 202400g (i.e 202.4 Kg) of CO2 were produced.

Explanation:

We'll begin by calculating the mass of CaCO3 present in 5×10² Kg of lime stone. This is illustrated below:

From the question given, the lime stone contains 92% of CaCO3.

Mass of CaCO3 = 92% x 5×10² Kg

Mass of CaCO3 = 92/100 x 5×10² Kg

Mass of CaCO3 = 460 Kg

Therefore, 460 kg of CaCO3 is present in the lime stone.

Next, we shall determine the mass of CaCO3 that was heated and the masses of CaO and CO2 produced from the balanced equation. This is illustrated below:

CaCO3(s) —> CaO(s) + CO2(g)

Molar mass of CaCO3 = 40 + 12 + (16x3) = 100g/mol

Mass of CaCO3 from the balanced equation = 1 x 100 = 100g

Molar mass of CaO = 40 + 16 = 56g

Mass of CaO from the balanced equation = 1 x 56 = 56g

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Mass of CO2 from the balanced equation = 1 x 44 = 44g

Summary:

From the balanced equation above,

100g of CaCO3 were heated to produce 56g of CaO and 44g of CO2.

A. Determination of the mass of quick lime, CaO produced by heating 5×10² Kg of lime stone.

5×10² Kg of lime stone contains 460 Kg (i.e 460×10³ g) of CaCO3.

From the balanced equation above,

100g of CaCO3 were heated to produce 56g of CaO.

Therefore, 460×10³g of CaCO3 will be heated to produce = (460×10³ x 56)/100 = 257600g of CaO.

Therefore, 257600g (i.e 257.6 Kg) of CaO were produced.

B. Determination of mass of carbon dioxide, CO2 produced by heating 5×10² Kg of lime stone.

5×10² Kg of lime stone contains 460 Kg (i.e 460×10³ g) of CaCO3.

From the balanced equation above,

100g of CaCO3 were heated to produce 44g of CO2.

Therefore, Therefore, 460×10³g of CaCO3 will be heated to produce = (460×10³ x 44)/100 = 202400g of CO2.

Therefore, 202400g (i.e 202.4 Kg) of CO2 produced.

Answer:

c. Chemical bonds are broken, and new ones are formed.

Explanation:

Hope this helps. :)

In a chemical reaction, chemical  bonds are broken, and new ones are formed.

Chemical reactions are defined as reactions which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical reaction.

There are several characteristics of chemical reactions like change in color, change in state , change in odor and change in composition . During chemical reaction there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

There are three types of chemical reactions:

1) inorganic reactions

2)organic reactions

3) biochemical reactions

During chemical reactions atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

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