A student pours a 10.0mL sample of a solution containing HC2H3O2(pKa=4.8) and NaC2H3O2 into a test tube. The student adds a few drops of bromocresol green to the test tube and observes a yellow color, which indicates that the pH of the solution is less than 3.8 . Based on this result, which of the following is true about the relative concentrations of HC2H3O2 and NaC2H3O2 in the original solution?

Answer:

6.5256×10¹⁴

Explanation:

n= v/24

v= n×25

v= 2.719×10¹³ × 24= 6.5256×10¹⁴ moles/dm³

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According to ideal gas equation, the volume occupied by 2.719 x 10¹³ moles of methane gas is 6174.76×10¹³cm³.

The ideal gas equation is a equation which is applicable in a hypothetical state of an ideal gas.It is a combination of Boyle's law, Charle's law,Avogadro's law and Gay-Lussac's law . It is given as, PV=nRT where R= gas constant whose value is 8.314.The law has several limitations.Ideal gases exist in hypothetical state.The law was proposed by Benoite Paul Emile Clapeyron in 1834.

Substituting values of pressure=1 atmosphere,number of moles=2.719 x 10¹³ ,R=8.314 ,T=273.15 K.

Therefore volume=nRT/P=2.719x 10¹³×8.314×273.15/1=6174.76×10¹³ cm³.

Thus, the volume occupied by 2.719 x 10¹³ moles of methane gas is 6174.76×10¹³cm³.

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Answer:

Pressure = 0.62 atm

Explanation:

[tex]V_{1}[/tex] = 85 [tex]cm^{3}[/tex], [tex]P_{1}[/tex] = 1.45 atm,  [tex]T_{1}[/tex] = 310 K, [tex]V_{2}[/tex] = 180 [tex]cm^{3}[/tex], [tex]T_{2}[/tex] = 280 K.

Applying the general gas law,

[tex]\frac{P_{1} V_{1} }{T_{1} }[/tex] = [tex]\frac{P_{2} V_{2} }{T_{2} }[/tex]

[tex]\frac{1.45*85}{310}[/tex] = [tex]\frac{P_{2}*180 }{280}[/tex]

[tex]P_{2}[/tex] = [tex]\frac{1.45*85*280}{180*310}[/tex]

   = [tex]\frac{34510}{55800}[/tex]

   = 0.62

[tex]P_{2}[/tex]  = 0.62 atm

The pressure when the volume is increased and the temperature reduced to the given values is 0.62 atm.

Explanation:

A physical change is a change that alters the physical properties of matter particularly the form and state.

In many cases the change is easily reversible. Examples are changes of state such as freezing, boiling, melting e.t.c

A chemical change is a change in which a new kind of matter is formed. It is always accompanied by energy changes which can either be evolution or absorption of heat or light or both.

The process is not easily reversible. Examples are combustion, rusting of iron, precipitation, e.t.c

During a chemical reaction, the reactants undergo a chemical change.

Answer: 12.2 moles

Explanation:

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

Answer:

1: false

2: B

Explanation:

I do not know the 3rd one

Answer:

32.4%

Explanation:

%Yield = Actual Yield/Theoretical Yield x 100% = (12.7/39.2)100% = 32.4%

Answer:

5.1 μg

Explanation:

Step 1: Given data

Volume of solution (V): 470.0 mL (0.4700 L)

Concentration of the solution (C): 8.8 × 10⁻⁵ mM (8.8 × 10⁻⁸ M)

Step 2: Calculate the moles (n) of AgO added

We will use the following expression.

n = C × V

n = 8.8 × 10⁻⁸ mol/L × 0.4700 L

n = 4.1 × 10⁻⁸ mol

Step 3: Calculate the mass (m) corresponding to 4.1 × 10⁻⁸ moles of AgO

The molar mass of AgO is 123.87 g/mol.

4.1 × 10⁻⁸ mol × 123.87 g/mol = 5.1 × 10⁻⁶ g

Step 4: Convert "m" to micrograms

We will use the conversion factor 1 g = 10⁶ μg.

5.1 × 10⁻⁶ g × 10⁶ μg/1 g = 5.1 μg

Answer:

C. Physical Change

Explanation:

Peeling a banana is not changing the banana's structure, it's still the same banana, but it looks different, which is a chemical change! Hope I helped!

Answer:

22.6%

Explanation:

I just answered and got it right

that is the correct answer don't worry :))

Answer:

A Variac or Powermite; gradually; 50-60%.

Explanation:

A chemical reaction can be defined as a chemical process which typically involves the transformation or rearrangement of the atomic, ionic or molecular structure of an element through the breakdown and formation of chemical bonds to produce a new compound or substance.

Some of the laboratory apparatus (equipment) used for conducting a chemical reaction are conical flask, Bunsen burner, beaker, tongs, crucible, round bottom flask etc.

In order to heat a round bottom flask in a heating mantle, plug the heating mantle into a Variac or Powermite which is typically used for controlling the level of temperature. Turn the heat up gradually, and do not exceed 50-60% of the maximum output of the device, so as to avoid any electrical issues such as overloading, short-circuit etc.

The safety precautions that must be taken when using a round bottom flask are;

I. A proper inspection of the round bottom flask for cracks, irregularities or any imperfection.

II. Ensure you avoid heating the flask while it is closed.

III. When suspending the round bottom flask on a stand, you should ensure that you use a clamp for stability.

Answer:

Taste comes from the stimulation of chemical receptors in nerve cells on the tongue by particular chemical structures of substances. If there are no chemical structures pertaining to any of the chemical sensors, the substance would appear to be tasteless. All of these chemicals interact with the sensors with the help of the medium of saliva which has a lot of water. For example: the salt sensors might be susceptible to ions and the sweet sensors might be susceptible to hydroxyl groups on the sugars.

Now, taste is not a very precise field of study. A same substance may taste subtly different to different people. Can we be sure that water has no taste? The chemical sensors are always exposed to water. It might be that there are no sensors for water. It might also be that the signal for water is negated as a background signal. If water did have a particular taste, one thing is for certain, we would be tasting water in every bite of food and even at times when we are not eating as we always have saliva in your mouth.

Hope this helps, have a wonderful day/night, and stay safe!

The number of atoms in 1 mole of carbon equals the number of atoms in 1 mole of boron is false because the molar mass of carbon is different from that of boron. Option A is correct.

From the listed option the number of atoms in 1 mole of carbon equals the number of atoms in 1 mole of boron is false because the molar mass of carbon is different from that of boron

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Answer:

577.6 mmHg

Explanation:

What is the conversion between atm (standard atmosphere) and mmHg (millimeters of mercury)?

Multiply the atm amount by 760 to get the mmHg amount.

19/25 * 760/1

19/5 * 152/1

(19*152)/5

2888/5

577 3/5 or 577.6 mmHg

Answer:

D

Explanation:

I hope this helps and have a great day

Answer:

it will A. d. e. f option above

4-,3-,2-,1-,0,1,2,3,4

Answer:

0.089

Explanation:

2.5/ 14= .178 then 0.178/ 2 again and you get 0.089

The moles of nitrogen in 2.5 grams of the compound is 0.089 moles. Thus option A is correct.

Moles can be calculated as the ratio of mass to molecular mass.

Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]

The mass of Nitrogen = 14 g/mol

The mass of diatomic nitrogen = 2 [tex]\times[/tex] mass of nitrogen

The mass of diatomic nitrogen = 2 [tex]\times[/tex] 14 g/mol

The mass of diatomic nitogen = 28 g/mol

The molecular weight of Nitrogen = 28g/mol

Given, the mass of Nitrogen = 2.5 g

Moles of nitrogen = [tex]\rm \dfrac{2.5}{28}[/tex]

Moles of Nitrogen = 0.089 moles.

The moles of nitrogen in 2.5 grams of the compound is 0.089 moles. Thus option A is correct.

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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: 720 g

Explanation:

To solve this we must be knowing each and every concept related to mole. Therefore, shivani measures out 6.0 moles of epsom salt (MgSO[tex]_4[/tex]) to put her bath. 1,566g MgSO[tex]_4[/tex] went in the bath.

A mole is merely a measuring unit. In reality, it is one of its International System of Units' seven foundation units. When current units are insufficient, new units are created.

Chemical reactions frequently occur at levels where employing grams would be inappropriate, but using absolute quantities of atoms/molecules/ions would also be misleading.

For all practical reasons, one mole of a substance in grams is nearly equal to 1 molecule for the compound per daltons.

Mathematically,

number of mole =given mass ÷ molar mass

number of mole=6.0 moles

molar mass of epsom= 261.47g/mol

substituting all the given values in the above equation, we get

6.0 moles =mass of epsom ÷ 261.47g/mol

mass of epsom =1,566g

Therefore, 1,566g  MgSO[tex]_4[/tex] went in the bath.

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Answer:0

Explanation:

Answer: a) [tex]Cu\rightarrow Cu^{2+}+2e^-[/tex]  : anode

b. [tex]2H^++2e^-\rightarrow H_2[/tex] : cathode

c. [tex]O^{2-}\rightarrow \frac{1}{2}O_2+2e^-[/tex]:  anode

Explanation:

Electrochemical cell is a device which converts chemical energy into electrical energy. It consist of two electrodes, anode and cathode.

Oxidation i.e. loss of electrons , which results in an increase in oxidation number occurs over anode.

Reduction i.e. gain of electrons, which results in decrease in oxidation number occurs over cathode.

a. [tex]Cu\rightarrow Cu^{2+}+2e^-[/tex]  : oxidation :  anode

b. [tex]2H^++2e^-\rightarrow H_2[/tex] : reduction : cathode

c. [tex]O^{2-}\rightarrow \frac{1}{2}O_2+2e^-[/tex]: oxidation : anode

Answer:

It does not change the identity of a substance. Sugar if dissolved in water is still sugar.

Explanation:

Answer:

B.  LiF < CH6N < H2O2 <I2

Explanation:

Find the molar mass of LiF

To do that, first look at the atomic mass of each element on the periodic table.

But they are one lithium atom and one fluorine atom

So you use this equation:

LiF has 25.9 g/mol

Now find the molar mass of CH6N.

To do that, first look at the atomic mass of each element on the periodic table.

But they are six hydrogen atoms, one carbon atom, and one nitrogen atom.

So you use this equation:

CH6N has 32 g/mol

Now find the molar mas of H2O2

To do that, first look at the atomic mass of each element on the periodic table.

But they are two oxygen atoms and two hydrogen atoms.

So you use this equation:

H2O2 has 34 g/mol.

Lastly, find the molar mass of I2

To do that, first look at the atomic mass of each element on the periodic table.

But they are two iodine atoms.

So you use this equation:

I2 has 253.8 g/mol

Now that we calculated the molar mass of all elements. We rank it in the following of increasing atomic mass.

Therefore, the final answer is B.  LiF < CH6N < H2O2 <I2

Hope it helped!

Answer:

*helps*

Explanation:

Answer:

number of protons is more than the number of electrons.

Explanation:

A cation is a positively charged ion.

An ion is an atom that has lost or gained electron(s). In an ion, the number of protons and electrons are not the same.

Number of protons is the number of positively charged particles

Number of electrons is the number of negatively charged particles.

 For a cation, which is positively charged, the number of protons is more than the number of electrons.

Therefore, in cations, we have more protons than electrons.