Why are prefixes often added to SI units?

Answer:

First one: group

Second one: period

Third one: number of valence electrons

Last one: increases

Answer:

yes, a compound can have more than one carbon-carbon double bond

Answer:

D

Explanation:

Scientists always perform tests and observe and measure in the physical world to prove their points or answer their questions.

Answer:

1. 1.72 moles of potassium.

2. All of the answers are true

3. Are used up during a reaction

Explanation:

Recall that the number of moles is obtained from;

Number of moles= Mass of potassium/ molar mass of potassium

Mass of potassium= 67 g

Molar mass of potassium= 39 gmol-1

Number of moles of K= 67 g/ 39 gmol-1

Number of moles = 1.72 moles of potassium.

2. When we look at all the options, we will realize that all the options are true. The rate of reaction doubles for each 10°C rise in temperature, increasing reactant concentration increases particle collision and ultimately increases the rate of reaction. Rate of reaction deals with rate of disappearance of reactants or rate of appearance of products.

3. Catalysts remain unchanged in a chemical reaction because they do not actually participate in the reaction. Hence they are not used up in any chemical reaction.

Answer:

Oxidation states are used in chemistry solutions. It is a bond in which electron transfers easily from one nucleus to another nucleus.

Explanation:

Answer:

B. Testing the electrical resistance of different materials.

Explanation:

An example of frontier research is " Testing the electrical resistance of different materials".

A frontiers Research Topic offers researchers the chance to present various viewpoints, approaches, and findings on a new or developing topic in a forum monitored by experts in the area but also published in a complete open-access journal.

Electrical resistance towards the current stream within an electrical circuit is measured by resistance. The Greek letter omega (ω) stands for ohms, which are used to evaluate resistance.

Therefore, the correct answer will be an option (B).

To know more about frontiers Research and electrical resistance

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Answer:

Silver ion

Explanation:

In an electrolytic cell, the positive ions known as the cations migrate to the negative electrode, the cathode where they accept electrons to become discharged as neutral atoms. Also, the negative ions known as the anions migrate to the positive electrode, the anode, where they give up their electrons to become discharged as neutral atoms.

From the question above, the only positive ion among the options given is the silver ion, Ag+, therefore, it is the correct option.

Answer: The IUPAC name of [tex]CH_3C\equiv CCH_2CH_2Cl[/tex] is 5-chloro-2-pentyne

Explanation:

1. First select the longest possible carbon chain.  For the number of carbon atom, we add prefix as 'meth' for 1, 'eth' for 2, 'prop' for 3, 'but' for 4, 'pent' for 5, 'hex' for 6, 'sept' for 7, 'oct' for 8, 'nona' for 9 and 'deca' for 10.

2. The longest possible carbon chain should contain all the bonds and functional groups.

3. The numbering is done in such a way that the carbon containing the functional group or substituent gets the lowest number.

4. The naming of alkane is done by adding the suffix -ane, alkene by adding the suffix -ene, alkyne.

Thus the IUPAC name of [tex]CH_3C\equiv CCH_2CH_2Cl[/tex] is 5-chloro-2-pentyne

Answer:

The answer is Observation 1 is a result of copper atoms losing two electrons.

Explanation:

The electrons result in the color change of the copper strip, causing the gray particles to join onto the metal.

Answer:

C

Explanation:

Observation 1 is a result of the copper atoms losing two electrons. It came out as the right answer.

The given question is incomplete. The complete question is as follows.

Pure potassiom hydrogen phthalate is used for standardization of the sodium hydroxide solution. Suppose that the potassium hydrogen phthalate is not completely dry. Will the reported molar concentration of the sodium hydroxide solution be too high, too low, or unaffected because of the moistness of the potassium hydrogen phthalate? Explain please.

Explanation:

When potassium hydrogen phthalate is not completely dry then it means there will be some water present in it. According to this, actual potassium hydrogen phthalate is diluted because of the presence of water molecules.

Hence, 1 mole of potassium hydrogen phthalate needs 1 mole of NaOH. And, at the equivalence point according to the concept of moles:

No. of moles of potassium hydrogen phthalate = No. of moles of NaOH

Also, the titration of potassium hydrogen phthalate concentration is less because of the presence of water then the number of moles of NaOH calculated will be less.

Thus, we can conclude that the molar concentration of the sodium hydroxide solution be too low.

Answer:

wrong.

Explanation: charged atoms have have more electrons than neural because  they charge it . a  neural atom has eaqual number of electrons and neutrons.

hope this helps(^人^)

Answer:

YES

Explanation:

The systematic study of the structure and behavior of the physical and natural world through observation and experiment.

Answer:

a

Explanation:

Answer:

2 degrees celcius

Explanation:

Answer:

It is the energy that is stored in bonds that hold particles together

Explanation:

Answer:

basic solution.

Explanation:

has a pH of 12.

it turns clear indicator pink.

it contains hydroxide ions which conduct electricity

Answer: [tex]PCl_5[/tex] is not an ionic compound.

Explanation:

An ionic compound is defined as the compound which is formed when electron gets transferred from one atom to another atom.  The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

Thus [tex]MoCl_6[/tex], [tex]RbCl[/tex], [tex]PbCl_2[/tex] and [tex]NaCl[/tex] are all ionic compounds.

Covalent compound is defined as the compound which is formed by the sharing of electrons between the atoms forming a compound. These are usually formed when two non-metals react.

Thus [tex]PCl_5[/tex] is a covalent compound as both Phosphorous and chlorine are non metals.

PCl₅ is not an ionic compound. Ionic or electrovalent compounds are formed

through the transfer of electrons in a chemical reaction. Metals and non-

metals mostly form ionic compounds.

Covalent bonding on the other involves the sharing of electrons between

two elements. Non-metals are mostly involved in this type of reaction.

PCl₅ possesses a covalent bond and not ionic as electrons are shared

between two non metals  which are phosphorus and chlorine.

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alkali metals

a.pex

yes

Answer:  [tex]C_6H_{14}[/tex] is a hydrocarbon.

Explanation:

Alcohols are the compounds which contain -OH as the functional group. Example: [tex]CH_3OH[/tex]

Amine are the compounds which contain [tex]-NH_2[/tex] as the functional group. Example: [tex]CH_3NH_2[/tex]

Ether are the compounds which contain [tex]ROR[/tex] as the functional group. Example: [tex]CH_3OCH_3[/tex]

Hydrocarbons are defined as the compounds in which bonds are present between carbon and carbon atoms. Hydrocarbons with single bond between carbon and carbon atoms are called as alkanes.The general formula for alkanes is [tex]C_nH_{2n+2}[/tex] Example: [tex]C_6H_{14}[/tex] which is named as hexane.

Answer:

D) Hydrocarbon

Explanation:

Completed the test and got it right

Answer:

1.24mol

Explanation:

m(MgO)=50g

molar mass=40.30g/mol (i search in google coz dosnt have book)

n=mass/molar mass

=50/40.30

=1.24mol

Answer:

It will produce 44 grams of carbon dioxide

Explanation:

Step 1: Data given

MAss of CaCO3 = 100 grams

Molar mass of CaCO3 = 100.09 g/mol

Mass of CaO produced = 56 grams

Molar mass of CaO = 56.08 g/mol

Step 2: The balanced equation

CaCO3 → CaO + CO2

Step 3: Calculate moles CaCO3

Moles CaCO3 = mass CaCO3 / molar mass CaCO3

Moles CaCO3 = 100 grams / 100.09 g/mol

Moles CaCO3 = 1.00 moles

Step 4: Calculate moles CaO

Moles CaO = 56 grams / 56.08 g/mol

Moles CaO = 1.00 moles

Step 5: Calculate moles CO2

For 1 mol CaCO3 we'll have 1 mol 1 mol CaO and 1 mol CO2

Step 6: Calculate mass CO2

Mass CO2 = moles CO2 * molar mass CO2

Mass CO2 = 1.00 moles * 44.0 g/mol

Mass CO2 = 44 grams

It will produce 44 grams of carbon dioxide

Answer:

Absolute Zero

Explanation:

at 0 Kelvin, nothing can move and entropy reaches 0

Answer:

absolute zero

Explanation:

Answer:

C. pH > pOH; Kw = 1.0 * 10^-14

Explanation:

The ion product of water, Kw = [H+]*[OH-] = 1.0 * 10^-14. It is a constant.

When an acid or base is added to water, its ion product does not change as it a constant. However, the relative concentrations of H+ ions and OH- ions will change depending on whether an acid or base is added to water.

When an acid is added to water, the concentration of H+ ions increases while that of OH- ions decreases, and vice versa.

Therefore, in the above situation where an acid is added to water, pH > pOH; Kw = 1.0 * 10^-14

Answer:

d. 0.9 mol

Explanation:

On this case we have to start with the formula of acetylene:

[tex]C_2H_2[/tex]

Now we can write the chemical reaction of combustion:

[tex]C_2H_2~+~O_2~->~CO_2~+~H_2O[/tex]

The next step is to balance the reaction:

[tex]2C_2H_2~+~5O_2~->~4CO_2~+~2H_2O[/tex]

The molar ratio between [tex]C_2H_2[/tex] and [tex]CO_2[/tex] is 2:4, so:

[tex]0.3~mol~C_2_H_2\frac{4~mol~CO_2}{2~mol~C_2H_2}=0.6~mol~CO_2[/tex]

The molar ratio between [tex]C_2H_2[/tex] and [tex]H_2O[/tex] is 2:2, so:

[tex]0.3~mol~C_2_H_2\frac{2~mol~H_2O}{2~mol~C_2H_2}=0.3~mol~H_2O[/tex]

The total moles would 0.6 + 0.3=0.9 moles.

I hope it helps!

Answer:

Therefore, 1.00 mole of the gas is present in the container.

Explanation:

The following data were obtained from the question:

Volume (V) = 22.41L

Temperature (T) = 273K

Pressure (P) = 101.325 kPa

Gas constant (R) = 8.31 L.kPa/mol.K.

Number of mole (n) =...?

The number of mole of the gas in the container can obtained by applying the ideal gas equation as illustrated below:

PV = nRT

Divide both side by RT

n = PV /RT

n =101.325  x 22.41 / 8.31 x 273

n = 1.00 mole.

Therefore, 1.00 mole of the gas is present in the container.

Answer:

1 mole of gas is contained in 22.41 liters at 101.325 kPa and 0ᴼC

Explanation:

Ideal gases are a simplification of real gases that is done to study them more easily. It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:  

P*V = n*R*T

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas.

In this case:

Replacing:

1 atm*22.41 L=n* 0.082 [tex]\frac{atm*L}{mol*K}[/tex]*273 K

Solving:

[tex]n=\frac{1 atm*22.41 L}{0.082\frac{atm*L}{mol*K} *273 K}[/tex]

n=1  mole

1 mole of gas is contained in 22.41 liters at 101.325 kPa and 0ᴼC

Answer:

[tex]V=1.61L[/tex]

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

[tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]

Next, we compute the reacting moles of each reactants:

[tex]n_{Mg}=3.712gMg*\frac{1molMg}{24.305 gMg}=0.153molMg[/tex]

[tex]n_{HCl}=1.385\frac{molHCl}{L}*0.1042L=0.144molHCl[/tex]

Then, as magnesium and hydrohloric acid are in a 1:2 molar ratio 0.153 moles of magnesium will completely react with 0.306 moles of hydrochloric acid yet we only have 0.144 moles, therefore, limiting reactant is hydrochloric acid. Thus, we compute the produced moles of hydrogen:

[tex]n_{H_2}=0.144molHCl*\frac{1molH_2}{2molHCl} =0.072molH_2[/tex]

Finally, we use the ideal gas equation with T=298K and 1atm (STP conditions) to compute the liters of hydrogen gas:

[tex]PV=nRT\\\\V=\frac{nRT}{P}=\frac{0.072mol*0.082\frac{atm*L}{mol*K}*273K}{1atm}\\ \\V=1.61L[/tex]

Best regards.

Answer: The percent yield for the [tex]NaBr[/tex] is, 86.7 %

Explanation : Given,

Moles of [tex]FeBr_3[/tex] = 2.36 mol

Moles of [tex]NaBr[/tex] = 6.14 mol

First we have to calculate the moles of [tex]NaBr[/tex]

The balanced chemical equation is:

[tex]2FeBr_3+3Na_2S\rightarrow Fe_2S_3+6NaBr[/tex]

From the reaction, we conclude that

As, 2 moles of [tex]FeBr_3[/tex] react to give 6 moles of [tex]NaBr[/tex]

So, 2.36 moles of [tex]FeBr_3[/tex] react to give [tex]\frac{6}{2}\times 2.36=7.08[/tex] mole of [tex]NaBr[/tex]

Now we have to calculate the percent yield for the [tex]NaBr[/tex].

[tex]\text{Percent yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100[/tex]

Experimental yield = 6.14 moles

Theoretical yield = 7.08 moles

Now put all the given values in this formula, we get:

[tex]\text{Percent yield}=\frac{6.14mol}{7.08mol}\times 100=86.7\%[/tex]

Therefore, the percent yield for the [tex]NaBr[/tex] is, 86.7 %