In a solution, the solvent is
ANSWER:
A. always water
B. dissolved in the solute
C. present in larger amount than the solute is
D. always nonpolar

Answer:

pH = 4.71

Explanation:

We can find the pH of a buffer (Mixture of weak acid: CH3COOH, and its conjugate base: CH3COONa) using H-H equation:

pH = pKa + log [CH3COONa] / [CH3COOH]

Where pH is the pH of the buffere = 4.74, pKa the pka of the buffer and [] could be taken as the moles of each reactant.

As initially [CH3COONa] = [CH3COOH], [CH3COONa] / [CH3COOH] = 1:

pH = pKa + log 1

4.74 = pKa

To solve this question we need to find the initial moles of each species, The CH3COONa reacts with HCl to produce CH3COOH. That means the moles of CH3COOH after the reaction are: Initial CH3COOH + Moles HCl

Moles CH3COONa: Initial CH3COONa - Moles HCl.

Moles CH3COOH:

0.100L * (0.50mol / L) = 0.050 moles CH3COOH + 0.0020 moles HCl =

0.052 moles CH3COOH

Moles CH3COONa:

0.100L * (0.50mol / L) = 0.050 moles CH3COONa - 0.0020 moles HCl =

0.048 moles CH3COONa

Using H-H equation:

pH = 4.74 + log [0.048 moles] / [0.052 moles]

The pH be after 0.0020 mol of HCl has been added to 100.0 mL of the buffer is 4.71.

Buffer solution is a mixture of weak acid and its conjugate base or vice versa.

We can calculate the pH of buffer solution by using Henderson - Hasselbalch Equation:

pH = pKa + log[CH₃COONa] / [CH₃COOH]

Initially concentration of CH₃COONa is equal to the concentration of CH₃COOH and equal becomes:

4.74 = pKa + log(1)

pKa = 4.74

Given moles of added HCl moles = 0.002 mole

Given molarity of each CH₃COOH & CH₃COONa = 0.50M

Given Volume = 100mL

We can calculate the moles by using the formula:

n = M × V

Moles of CH₃COOH & CH₃COONa = 0.100 × 0.50 = 0.050 moles

Moles of CH₃COOH = 0.050moles CH₃COOH + 0.0020moles HCl =

0.052moles CH₃COOH

Moles of CH₃COONa = 0.050moles CH3COONa - 0.0020moles HCl =

0.048moles CH₃COONa

Now, resultant pH will be:

pH = 4.74 + log [0.048 moles] / [0.052 moles]

pH = 4.71

Hence, pH of resultant solution is 4.71.

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Answer:

antimony-121 has the highest percent natural abundance

Explanation:

percent natural abundance;

121.76 = 120.90 x + 122.90 (1 - x)

121.76 = 120.90 x + 122.90 - 122.90x

121.76 = -2x + 122.90

121.76 - 122.90 = -2x

x= 121.76 - 122.90/ -2

x= 0.57

Where x and 1 - x refers to the relative abundance of each of the isotopes

Percent natural abundance of antimony-121 = 57 %

Percent natural abundance of antimony-123 = (1 - 0.57) = 43%

Let us remember that isotopy refers to a phenomenon in which atoms of the same element have the same atomic number but different mass numbers. This results from differences in the number of neutrons in atoms of the same element.

We can clearly see that antimony-121 has the highest percent natural abundance.

Answer:

0.377 J/gºC

Explanation:

From the question given above, the following data were obtained:

Mass of metal (Mₘ) = 65.3 g

Initial temperature of metal (Tₘ) = 99.8 °C

Mass of water (Mᵥᵥ) = 43.7 g

Initial temperature of water (Tᵥᵥ) = 25.7 °C

Equilibrium temperature (Tₑ) = 34.5 °C

Specific heat capacity of water (Cᵥᵥ) = 4.18 J/gºC

Specific heat capacity of metal (Cₘ) =?

The specific heat capacity of metal can be obtained as illustrated below:

Heat lost by metal = heat gained by water.

MₘCₘ(Tₘ – Tₑ) = MᵥᵥCᵥᵥ(Tₑ – Cᵥᵥ)

65.3 × Cₘ (99.8 – 34.5) = 43.7 × 4.18 (34.5 – 25.7)

65.3Cₘ × 65.3 = 182.666 × 8.8

4264.09Cₘ = 1607.4608

Divide both side by 4264.09

Cₘ = 1607.4608 / 4264.09

Cₘ = 0.377 J/gºC

Therefore the specific heat capacity of the metal is 0.377 J/gºC

Answer:stow the hairspray

Explanation:

Answer:

b. The anion affects the color of the solution more than the intensity of the color.

Explanation:

An ionic compound is one that is made up of ions held together by electrostatic forces. The ions are made up of positively charged ions known as cations and negatively charged ions known as anions. In compounds with a high ionic attribute, anions produce colorless compounds. But compounds that have less ionic attributes produce deeper colors like black and red. When in solutions, ionic compounds take on color and this is because of the anion that absorbs infrared light energy.

Answer:

the fraction of collisions with energy greater than Eact

Explanation:

The activation energy of a reaction stands as a sort of energy barrier between reactants and products. It is only reactants that possesses energy greater than the activation energy that can be converted from reactants to products.

When the temperature of the system is increased, more particles acquire energy greater than the activation energy. Hence, the fraction of collisions with energy greater than the activation energy increases so the rate of reaction increases likewise.

Answer:

Please find the complete solution in attached file.

Explanation:

Periodic law is the the properties of the elements that repeat in a regular way as the atomic numbers increase.

Periodic chart organized collection of all chemical elements arranged roughly according to increasing atomic weight. The periodic recurrence of several features in the elements was originally identified by Dmitry I. Mendeleyev in 1869.

1. This is a vertical arrangement of elements in the periodic table   group

2. This is a horizontal arrangement of elements in the periodic table   period

3. The properties of the elements repeat in a regular way as the atomic numbers increase periodic law

4. Element 19 begins this arrangement in the periodic table period

5. The chemical properties of elements 12, 20, and 38 demonstrate this principle.  periodic law

Therefore, periodic law is the the properties of the elements that repeat in a regular way as the atomic numbers increase.

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Answer:

1. Weak acid calculation

2. Strong base calculation

3. Strong base calculation

4. Strong base calculation

Explanation:

1. Zero equivalents of base added  

2. 0.15 equivalents of base added  

3. One equivalent of base added  

4. 1.75 equivalents of base added

The equivalents of acetic acid are:

0.100L * (0.300mol/L) = 0.0300 moles of acetic acid = 0.0300Eq.

1. With Zero equivalents of base added you will calculate pH using weak acid calculation because you have only acetic acid (Weak acid) in the solution.

2. When 0.15 equivalents of base are added all the acid reacted and 0.15-0.03 = 0.12 equivalents of Strong base are in excess. With these equivalents and the volume we can find pH using strong base calculation.

3 and 4. As with 0.15 eq. added the 1 eq. and 1.75 eq. produce an excess of strong base and the pH must be calculated by using strong base calculation

The main importance of the titration curve is that it is used show how the pH of the solution changes as a titrant  is added to the solution.

A titration curve is a plot of pH of the system against the volume of titrant added. The question is incomplete but I will try to explain what a titration curve is.

The main importance of the titration curve is that it is used show how the pH of the solution changes as a titrant  is added to the solution.

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Answer:

less than 5 centimeters because it is a nonvascular plant

Explanation:

Mosses are a group of plants under the division Bryophyta. They are said to be the most primitive plant life in existence as they lack true roots, stems and leaves. They also lack vascular system, hence, they are regarded as non-vascular plants. They usually grow in very small sizes (about 0.2 - 10cm).

According to this question, Penny bought a club moss plant for her water garden and needs to know how tall the plant will grow so she know how much space it will need. Since it is a miss plant that lacks vascular tissues i.e. nonvascular, it will likely grow less than 5 centimeters in height.

Answer:

d

Explanation:

Answer:

none All have the same kinetic energy

Explanation:

Answer:

The correct option is A

Explanation:

Some amino acids, called glucogenic amino acids, when catabolized convert there carbon backbones to tricarboxylic acid (TCA) cycle intermediates. These intermediates can be subsequently metabolized into carbon dioxide and water with the release of ATP or the formation of glucose (known as gluconeogenesis.

All amino acids (with the exception of leucine and lysine) are glucogenic and can thus generate the carbon backbones required for gluconeogenesis. Thus, the correct option is a.

Answer: The number of series in Mendeleev's Periodic table is 12.

Explanation:

Horizontal rows present in the periodic table are called periods. Vertical rows in the periodic table are called series.

Mendeleev gave periodic table in the year 1869 by arranging elements according to their atomic weights a in tabular form.  

Mendeleev's periodic table depicts 12 periods/series.

Thus, we can conclude that the number of periods/series in Mendeleev's Periodic table is 12.

Answer:

0.25 mm> 0.50 mm > 0.75 mm> 1mm> 1.25 mm

Explanation:

Capillary movement involves the movement of liquid up through a capillary tube.

Looking at the question, we can see all the various diameters of the capillary tube are involved.

Note that, that the narrower the diameter of the capillary tube, the better the capillary action of the liquid (the liquid rises more now than then).

Answer: It is true about the type of reaction that it is a single replacement reaction, and the cations in the two ionic compounds are different.

Explanation:

When one element in a compound is replaced by another element in a chemical reaction then it is called a single replacement reaction.

For example, [tex]K + NaCl \rightarrow KCl + Na[/tex]

Here, potassium metal is replacing the sodium metal in the sodium chloride compound.

As metals become cation by losing an electron in a chemical reaction.

Thus, we can conclude that it is true about the type of reaction that it is a single replacement reaction, and the cations in the two ionic compounds are different.

Answer: Its A

Explanation:

a single replacement reactions, and the ANIONS in the two ionic compounds are different

Answer:

25.08 grams of O₂ are needed to react with 8.15 g of C₂H₂.

Explanation:

The balanced reaction is:

2 C₂H₂ + 5 O₂ → 4 CO₂ + 2 H₂O

By reaction stoichiometry, the following amounts of moles of each compound participate in the reaction:

The molar mass of each compound is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

Then you can apply the following rule of three: if by stoichiometry 52 grams of C₂H₂ react with 160 grams of O₂, 8.15 grams of C₂H₂ react with how much mass of O₂?

[tex]mass of O_{2} =\frac{8.15 grams of C_{2} H_{2}*160 grams of O_{2} }{52 grams of C_{2} H_{2}}[/tex]

mass of O₂= 25.08 grams

25.08 grams of O₂ are needed to react with 8.15 g of C₂H₂.

Answer:

Excluding any secondary chemical reactions,

which would be more effective as an antifreeze; a

solution containing

Select one:

25m CH3OH

the combination of 25m CH3OH and 25m

KCI.

25m KCI.

Explanation:

Antifreeze is the one that reduces the freezing point of a solvent further and will not allow the solvent to freeze.

Among the given options, the correct option is:

25 m CH3OH and 25m KCl.

Since, KOH is a strong electrolyte and dissociates into two ions.

So, the freezing point of solvent decreases further.

Answer:

On the basis of your knowledge of the reaction of halogens with alkanes, decide which product you would not expect to be formed in even small quantities in the bromination of ethane?

A) BrCH2CH2Br

B) CH3CH2CH2Br

C) CH3CHBr2

D) CH3CH2CH2CH3

E) BrCH2CH2CH2CH2Br

Explanation:

The reaction of ethane with bromine in presence of UV light forms mono substituted ethane at all primary and secondary carbons.

This is an example of free radical substitution.

The structure of ethane and its bromination is shown below:

Among the given options that which is not possible to form is option B) that is CH3CH2CH2Br(propyl bromide).

Remaining all other products are possisble to form on free radical substitution of ethane.

Answer:

amount, pH value.

Explanation:

The buffer range is the pH range in which the buffer performs optimally, i.e., neutralizes even when a strong acid or base is introduced to it and resists any major change in its pH value.

The buffer capacity is the amount of acid or base that can be added before the pH of the buffer solution changes significantly.

Thus, the final statement becomes,

Buffer capacity is the amount of acid or base a buffer can handle before pushing the pH value outside of the buffer range.

Answer:

Amount

pH value

Buffer capacity is the amount  of acid or base a buffer can handle before pushing the pH  outside of the buffer range.

A buffer however consists of a weak acid and its conjugate base.Its major advantage is the ability to resist changes in pH when an acid or a base is added to the solution.

The human blood is also an example of a buffer solution as it is able to resist changes in pH when we eat or drink certain types of food.

An example of a buffer include acetic acid (HC₂H₃O₂) which is a weak acid and sodium acetate (NaC₂H₃O₂) which is a salt derived from that acid).

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Answer:

ΔH = -2446J

Explanation:

Based on the reaction:

2 Na(s) + Cl2(g) → 2NaCl

We can find the enthalpy of this reaction using Hess's law:

The enthalpy of a reaction is equal to the sum of the enthalpy of products times their reaction quotient subtracting the enthalpy of reactants times their reaction quotient. For the reaction of the problem:

ΔH = 2ΔH(NaCl) - [2ΔH(Na) + ΔHCl2)]

ΔH(NaCl) = 670J

ΔH(Na) = 235cal * (4.184J/1cal) = 983J

ΔHCl2 = 435cal * (4.184J/1cal) = 1820J

ΔH = 2*670J - [2*983J + 1820J]

ΔH = 1340J - [3786J]

Answer:

the heat content of a system at constant pressure

Explanation:

Answer: Moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, [tex]CH_{4}[/tex].

Explanation:

Given: Mass of methane = 146.6 g

As moles is the mass of a substance divided by its molar mass. So, moles of methane (molar mass = 16.04 g/mol) are calculated as follows.

[tex]Moles = \frac{mass}{molar mass}\\= \frac{146.6 g}{16.04 g/mol}\\= 9.14 mol[/tex]

The given reaction equation is as follows.

[tex]C + 2H_{2} \rightarrow CH_{4}[/tex]

This shows that 2 moles of hydrogen gives 1 mole of methane. Hence, moles of hydrogen required to form 9.14 moles of methane is as follows.

[tex]Moles of H_{2} = \frac{9.14}{2}\\= 4.57 mol[/tex]

Thus, we can conclude that moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, [tex]CH_{4}[/tex].

Answer:

[Na⁺] = 1.99 M

Explanation:

Na₂S is a ionic salt that can be dissociated.

Dissociation equation is:

Na₂S  →  2Na⁺  +  S⁻²

1 mol of sodium sulfide can give 2 moles of sodium cation.

We convert moles of salt: 78 g . 1mol / 78.06 g = 0.999 moles

As ratio is 1:2, after dissociation we have (0.999 . 2) = 1.998 moles of Na⁺

Molarity is a type of concentration.

It indicates moles of solute in 1 L of solution and in this case, we have 1 L as final voulme.

Moles of Na⁺ are 1.998 moles. Then molarity (mol/L) is:

M =1.99 mol/L  

Explanation:

A compound containing only two elements is called a binary compound.

(a). The compound HCN contains a hydrogen ion and cyanide ion. Hence, the name of HCN is hydrogen cyanide.

An aqueous solution of hydrogen cyanide is known as hydrogen cyanide solution.

(b). The compound HF contains a hydrogen ion and a fluorine ion. The suffix -ide will be added to its name. So, the name of this compound is hydrogen fluoride.

An aqueous solution of HF is known as hydrogen fluoride.

(c). The compound [tex]H_{2}S[/tex] contains two hydrogen atoms and one sulfur atom. The suffix -ide will be added to its name. So, the name of this compound is hydrogen sulfide.

An aqueous solution of this compound is known as hydrogen sulfide solution.

Answer:

only one substrate could be converted to product by the enzyme

Explanation:

If an enzyme obeys the lock and key model, it then follows that the design of the enzyme is unique to a particular substrate.

Just as only the correct key can effectively fit into a lock, only the appropriate substrate whose design matches that of the enzyme can fit into the enzyme.

Owing to the lock and key model of enzyme activity, only one enzyme could interact with a substrate to yield particular product.

Answer:

both

Explanation:

A homolytic fission is said to have occurred when the breakage of a bond between two atoms leaves each of the bonding atoms with equal number of electrons. Homolytic fission often results in the creation of radicals.

Since homolytic fission yields two species with equal number of electrons(usually odd number of electrons), the products of such process can not be charged. They can not be nucleophiles because nucleophiles need to possess two electrons which can be shared with another chemical specie.

Answer:

The correct answer is A. 59.

Explanation:

The formula for finding the amount of radio active substance that remains after decomposition is A = N(1/2) ^y, where A is the mass remaining, N is the original mass of a radioactive sample and y is the number of half life. In this case, N = 10 g and y = 6/2 = 3. So A is given by 10 x (1/2)^3, which is 10 x 1/2 x1/2 x 1/2 = 1.25 grams.

Answer:

heat; temperature; surrounding; insulated.

Explanation:

A calorimeter can be defined as a scientific instrument or device designed and developed for measuring the heat involved in reactions or other processes, especially by taking the measurement of the temperature of the materials surrounding the process.

Basically, a calorimeter is insulated using materials with very high level of resistivity so as to prevent heat transfer to the outside of the device (calorimeter). Some of the components that make up a simple calorimeter are thermometer, an interior styrofoam cup, an exterior styrofoam cup, cover, etc.

Additionally, a calorie refers to the amount of heat required to raise the temperature of a gram of water by one degree Celsius (°C).

Answer:

A

Explanation:

because solid stick together like magnetic and can feel every vibration

Answer:D

Explanation: on the surface of a solid