Explanation:
Mike drives his car 60 km in 55minutes. What is its average speed in kilometers per hour ? A train travels 120 km in 2 hours and 30 .
yclohexane (C6H12) is soluble in benzene (C6H6) and insoluble in water. This is because benzene has a
Answer:
Cyclohexane (C6H12) Is Soluble In Benzene (C6H) And Insoluble In Water. This Is Because Benzene Has A Lower Density Than Water Lower Heat Capacity Than Water Lower Boiling Point Than Water Lower Polarity Than Water.
Cyclohexane is insoluble in water solvents, but it is soluble in Benzene, because it is a nonpolar Solvent.
Why cyclohexane dissolves in Benzene but not in water?Solubility in chemistry depend upon the nature of the solvent and the solute "like dissolves like".
Cyclohexane and Benzene both are a nonpolar solute and only dissolve in nonpolar solvent.
Hence, water is a polar solvent cyclohexane it is not soluble in water.
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For a science project, Janet performs four experiments that are supposed to show a chemical reaction. She displays her results in a table.A 4-column table with 4 rows. The first column titled experiment has entries 1, 2, 3, 4. The second column titled substances has entries water + heat, vinegar + baking soda, cabbage juice + lemon juice, liquid A + liquid B. The third column titled evidence of reaction has entries gas formation, gas formation, color change, precipitate formation. The fourth column titled Chemical Reaction ? has entries yes, yes, yes, yes.In the column titled "Chemical reaction?,” which experiment’s data should be changed to "No”?Experiment 1Experiment 2Experiment 3Experiment 4
Answer:
Experiment 1
Explanation:
I don’t know if this is right
What are the concentrations of hydroxide and hydronium ions in a solution with a pH of 10.2? 1.4 × 10–4 M H3O+ and 7.1 × 10–11 M OH– 3.8 × 10–6 M H3O+ and 2.6 × 10–9 M OH– 8.3 × 10–9 M H3O+ and 1.2 × 10–6 M OH– 6.3 × 10–11 M H3O+ and 1.6 × 10–4 M OH–
Answering:
It is D
Explanation:
Just took the test
The concentration of hydronium ion [H₃O⁺] and hydroxide ion [OH¯] are:
1. Concentration of hydronium ion [H₃O⁺] is 6.3×10¯¹¹ M 2. Concentration of Hydroxide ion [OH¯] is 1.6×10¯⁴ MThe pH of a solution is simply a measure of the acidic or alkalinity of the solution.
The concentration of hydronium ion [H₃O⁺] and hydroxide ion [OH¯] can be obtained as illustrated below:
Step 1Data obtained from the question
pH = 10.2
Concentration of hydronium ion [H₃O⁺] =…? Concentration of Hydroxide ion [OH¯] =…? Step 2Determination of the concentration of hydronium ion [H₃O⁺]
pH = 10.2
Concentration of hydronium ion [H₃O⁺] =…?pH = –log[H₃O⁺]
10.2 = –log[H₃O⁺]
Multiply though by –1
–10.2 = log[H₃O⁺]
Take antilog of –10.2
[H₃O⁺] = antilog(–10.2)
[H₃O⁺] = 6.3×10¯¹¹ MStep 3:Determination of the pOH
pH = 10.2
pOH =?
pH + pOH = 14
10.2 + pOH = 14
Collect like terms
pOH = 14 – 10.2
pOH = 3.8Step 4Determination of the concentration of Hydroxide ion [OH¯].
pOH = 3.8
Concentration of Hydroxide ion [OH¯] =…?pOH = –log[OH¯]
3.8 = –log[OH¯]
Multiply through by –1
–3.8 = log[OH¯]
Take the antilog of –3.8
[OH¯] = antilog(–3.8)
[OH¯] = 1.6×10¯⁴ MSUMMARY:1. Concentration of hydronium ion [H₃O⁺] = 6.3×10¯¹¹ M
2. Concentration of Hydroxide ion [OH¯] = 1.6×10¯⁴ M
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In an experiment, a student was assigned to find the formula of an unknown hydrate that weighed 15.67g. The anhydrate, XCO3 (molar mass = 84.32 g/mol), weighed 7.58 g after all the water was driven off. Determine the moles of water per one mole of anhydrate.
Answer:
5.0 moles of water per one mole of anhydrate
Explanation:
To solve this question we must find the moles of the anhydrate. The difference in mass between the dry and the anhydrate gives the mass of water. Thus, we can find the moles of water and the moles of water per mole of anhydrate:
Moles Anhydrate:
7.58g * (1mol / 84.32g) = 0.0899 moles XCO3
Moles water:
15.67g - 7.58g = 8.09g * (1mol / 18.01g) = 0.449 moles H2O
Moles of water per mole of anhydrate:
0.449 moles H2O / 0.0899 moles XCO3 =
5.0 moles of water per one mole of anhydrate
Lactic acid, which is found in milk products, has a pKa of 3.85. A 50.0 mL solution of 0.05 M lactic acid is titrated with 0.025 M sodium hydroxide. What is the pH of the solution after 64.0 mL of the sodium hydroxide has been added
4. True or False. The longer a wire the greater its resistance.
O
True
False
Answer:
TRUE
Explanation:
The total length of the wires will affect the amount of resistance. The longer the wire, the more resistance that there will be.
Answer:
true
Explanation:
what is the colour of litmus in a solution of ammonium hydroxide?
Answer:
Red litmus turns blue
Explanation:
Hope it helps
g how many moles of NO are produced if 2.5 mol of O2 react completely with 4.0 mol of NH3 (molar mass of NO
Answer:
2 moles of NO
Explanation:
Our reaction is:
4NH₃ + 5O₂ → 6H₂O + 4NO
4 moles of ammonia react to 5 moles of oxygen in order to produce 6 moles of water and 4 moles of NO
We need to determine the limiting reactant:
Ratio is 4:5, As 4 moles of ammonia react to 5 moles of oxygen and we have 4 moles, we definetely need 5 moles, but the problem is, we only have 2.5 moles of O₂. Oxygen is the limting reagent.
5 moles of O₂ produce 4 moles of NO, according to stoichiometry
2.5 moles of O₂ may produce (2.5 . 4) / 5 = 2 moles of NO
The carbon-oxygen double bond, or carbonyl, is a key feature of many organic molecules. Two resonance structures can be used to illustrate the properties of the carbonyl structure as provided. In analyzing the minor resonance structure, what can we conclude about the Lewis acid properties of the carbonyl
The question is incomplete, the complete question is shown in the image attached to this answer
Answer:
B
Explanation:
A Lewis acid is specie that has vacant orbitals and is able to accept a lone pair of electrons while a Lewis base is any specie having a lone pair of electrons which can be donated to another chemical specie.
Hence a Lewis acid accepts a lone pair of electrons while a Lewis base donates a lone pair of electrons.
From the resonance structure shown, the carbon atom in the carbonyl compound ought to function as the Lewis acid since it is electrophilic (electron deficient).
Answer: The Carbon atom in the carbonyl will act as a lewis acid and will accept a pair of electrons
Explanation:
In the minor resonance structure for the carbonyl group, we observe a positive formal charge on the carbon atom. Because of its positive formal charge, the carbon atom will act as a Lewis acid and accept a pair of electrons to stabilize that formal charge.
A chemical bond formed when two atoms share three pairs of electrons is a ________ bond; it is best described as ________.
Answer:
Explanation:
A chemical bond formed when two atoms share three pairs of electrons is a triple bond; it is best described as covalent.
Based on the understanding of the mechanism of a single displacement reaction, which of the following chemical equations represent a single displacement reaction? Select all that apply.
A. NaCl + AgNO3 → NaNO3 + AgCl
B. Cu + AgNO3 → CuNO3 + Ag
C. 2NaBr + Cl2 → 2NaCl + Br2
D. F2 + 2NaBr → 2NaF + Br2
E. KOH + HCl → KCl + H2O
Answer:
B. Cu + AgNO3 → CuNO3 + Ag
C. 2NaBr + Cl2 → 2NaCl + Br2
D. F2 + 2NaBr → 2NaF + Br2
Explanation:
There are several types of reactions in chemistry, of which one of them is the SINGLE DISPLACEMENT REACTION. Single displacement reaction is that reaction in which only one element in a compound is displaced/replaced by another element.
The following reactions given in this question are examples of single displacement reactions;
- Cu + AgNO3 → CuNO3 + Ag
- 2NaBr + Cl2 → 2NaCl + Br2
- F2 + 2NaBr → 2NaF + Br2
* In the first reaction, silver (Ag) is displaced by copper (Cu)
* In the second reaction, bromine (Br) is displaced by chlorine (Cl)
* In the third reaction, bromine (Br) is displaced by fluorine (F)
The single replacement reaction are;
Cu + AgNO3 → CuNO3 + Ag. F2 + 2NaBr → 2NaF + Br2 2NaBr + Cl2 → 2NaCl + Br2A single displacement reaction is one in which one of the reactants replaces another. A typical example is the reaction; A + BC ---> AB + C.
Having this in mind, we can see that the reactions that correspond to a single replacement reaction are;
Cu + AgNO3 → CuNO3 + Ag. F2 + 2NaBr → 2NaF + Br2 2NaBr + Cl2 → 2NaCl + Br2Learn more about single replacement reaction: https://brainly.com/question/1984022
How many atoms do 24 g of carbon have
1.2 × 10²⁴ atoms C
General Formulas and Concepts:Chemistry
Atomic Structure
Reading a Periodic TableMolesAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisMath
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right Explanation:Step 1: Define
Identify variables
[Given] 24 g C
[Solve] atoms C
Step 2: Identify Conversions
Avogadro's Number
[PT] Molar Mass of C: 12.01 g/mol
Step 3: Convert
[DA] Set up: [tex]\displaystyle 24 \ g \ C(\frac{1 \ mol \ C}{12.01 \ g \ C})(\frac{6.022 \cdot 10^{23} \ atoms \ C}{1 \ mol \ C})[/tex][DA] Divide\Multiply [Cancel out units]: [tex]\displaystyle 1.2034 \cdot 10^{24} \ atoms \ C[/tex]Step 4: Check
Follow sig fig rules and round. We are given 2 sig figs.
1.2034 × 10²⁴ atoms C ≈ 1.2 × 10²⁴ atoms C
Find the mass of 0oC ice that 10 gof 100oC steam will completely melt. Latent heat of fusion of ice is 80cal/g oCand heat of vaporization of water 540 cal/g oC ?
Answer:
The right approach is "80 g".
Explanation:
Given:
[tex]L_f=80 \ Cal/g[/tex]
[tex]L_v=540 \ Cal/g[/tex]
[tex]S=1 \ Cal/g[/tex]
Now,
The amount of heat cooling will be:
= [tex]mL_v+mS \Delta T[/tex]
= [tex](10\times 540)+10\times 1\times (100-0)[/tex]
= [tex]5400+1000[/tex]
= [tex]6400 \ Cal[/tex]
then,
⇒ [tex]m_{ice} L_f=6400[/tex]
[tex]m_{ice}\times 80=6400[/tex]
[tex]m_{ice}=\frac{6400}{80}[/tex]
[tex]=80 \ g[/tex]
Please someone help me!
I need this done ASAP *URGENT*
I Need this done before Thursday or Friday because Friday is my last day of school so please finish this today!
Best answer gets BRAINLIEST
PLEASE HURRY AND ANSWER ALL QUESTIONS CORRECTLY
NO LINKS OR ANSWER REPORTED
What’s the difference worksheet
Atoms,molecules,elements and compounds
PLEASE PLEASE PLEASE PLEASE PLEASEEEEEEE ANSWER THIS I only have TWO days of school left! And I need this done quickly
Answer:
A molecule is the smallest particle of a substance that is made up of 2 or more atoms
An atom is the smallest particle of any pure element
An element is a substance that cannot be broken chemical and physical processes
A molecule is known as the building block of matter
A compound is a chemical substance that is made up of 2 more more different atoms bonded together
What is the molarity and normality of solution containing 80 g of NaOH dissolved in 2.0 liter of the solution?
AAnswer:
Explanation:
Consider a hypothetical metal that has a density of 3.55 g/cm3, an atomic weight of 40.48 g/mol, and an atomic radius of 0.135 nm. Compute the atomic packing factor if the unit cell has tetragonal symmetry, values for the a and c lattice parameters are 0.545 and 0.255, respectively.
Answer:
0.5447
Explanation:
The atomic packing fraction factor is given by
APF = Volume of sphere/ Volume of unit cell
[tex]APF = \frac{N\times V_N}{V_C}[/tex]
The atomic radius = 0.135 nm
The Density of the metal = 3.55 g/cm^3
To calculate the number of atoms
= desnsity/(atomic radius×Avagadro's number)
Putting values and solving we get
the number of atoms = 4
Now,
[tex]APF = \frac{4\times 4/3\pi(0.135\times10^{-9})^3}{(0.545\times10^{-9})^2(0.255\times10^{-9})}[/tex]
Solving we get
APF = 0.54427
If an ice cube weighing 25.0 g with an initial
temperature of -7.5 °C is placed in an insulated cup
containing 200 ml of water that has an initial
temperature of 15.7 °C, what is the final temperature of
the water?
(Specific heat capacity of water is 4.18 J/°C.g.
Density of water is 1 g/ml)
Answer:
11
∘
C
Explanation:
As far as solving this problem goes, it is very important that you do not forget to account for the phase change underwent by the solid water at
0
∘
C
to liquid at
0
∘
C
.
The heat needed to melt the solid at its melting point will come from the warmer water sample. This means that you have
q
1
+
q
2
=
−
q
3
(
1
)
, where
q
1
- the heat absorbed by the solid at
0
∘
C
q
2
- the heat absorbed by the liquid at
0
∘
C
q
3
- the heat lost by the warmer water sample
The two equations that you will use are
q
=
m
⋅
c
⋅
Δ
T
, where
q
- heat absorbed/lost
m
- the mass of the sample
c
- the specific heat of water, equal to
4.18
J
g
∘
C
Δ
T
- the change in temperature, defined as final temperature minus initial temperature
and
q
=
n
⋅
Δ
H
fus
, where
q
- heat absorbed
n
- the number of moles of water
Δ
H
fus
- the molar heat of fusion of water, equal to
6.01 kJ/mol
Use water's molar mass to find how many moles of water you have in the
100.0-g
sample
100.0
g
⋅
1 mole H
2
O
18.015
g
=
5.551 moles H
2
O
So, how much heat is needed to allow the sample to go from solid at
0
∘
C
to liquid at
0
∘
C
?
q
1
=
5.551
moles
⋅
6.01
kJ
mole
=
33.36 kJ
This means that equation
(
1
)
becomes
33.36 kJ
+
q
2
=
−
q
3
The minus sign for
q
3
is used because heat lost carries a negative sign.
So, if
T
f
is the final temperature of the water, you can say that
33.36 kJ
+
m
sample
⋅
c
⋅
Δ
T
sample
=
−
m
water
⋅
c
⋅
Δ
T
water
More specifically, you have
33.36 kJ
+
100.0
g
⋅
4.18
J
g
∘
C
⋅
(
T
f
−
0
)
∘
C
=
−
650
g
⋅
4.18
J
g
∘
C
⋅
(
T
f
−
25
)
∘
C
33.36 kJ
+
418 J
⋅
(
T
f
−
0
)
=
−
2717 J
⋅
(
T
f
−
25
)
Convert the joules to kilojoules to get
33.36
kJ
+
0.418
kJ
⋅
T
f
=
−
2.717
kJ
⋅
(
T
f
−
25
)
This is equivalent to
0.418
⋅
T
f
+
2.717
⋅
T
f
=
67.925
−
33.36
T
f
=
34.565
0.418
+
2.717
=
11.026
∘
C
Rounded to two sig figs, the number of sig figs you have for the mass of warmer water, the answer will be
T
f
=
11
∘
C
Explanation:
If more powdered Kool-Aid is added to the same amount of water, what happens to the solution (the answer I clicked I don’t know if correct or not)
Answer:
its option 3
Explanation:
the molarity of the solution increases
If more powdered Kool-Aid is added to the same amount of water, then the molarity of the solution increases because there are more solute particles in the solution.
What is Molarity?Molarity of a given solution is known as the total number of moles of solute per litre of the solution. A solution that is 1.00 molar (written 1.00 M) contains 1.00 mole of solute for every liter of solution.
Molarity = (No. of moles of solute ÷ Volume of solution in liters)
The unit of molarity is mol L⁻¹.
Molarity is temperature dependent because as temperature changes, volume of the solution also changes.
Therefore, If more powdered Kool-Aid is added to the same amount of water, then the molarity of the solution increases because there are more solute particles in the solution.
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What is the molar concentration of 29 g of Mg(OH)2 dissolved in 1.00 L of water
Answer: The molar concentration of 29 g of [tex]Mg(OH)_{2}[/tex] dissolved in 1.00 L of water is 0.497 M.
Explanation:
Given: Mass = 29 g
Volume = 1.00 L
Moles is the mass of substance divided by its molar mass. So, moles of [tex]Mg(OH)_{2}[/tex] is as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{29 g}{58.32 g/mol}\\= 0.497 mol[/tex]
Molarity is the number of moles of a substance divided by volume in liter.
Hence, molarity of the given solution is as follows.
[tex]Molarity = \frac{moles}{Volume (in L)}\\= \frac{0.497 mol}{1.00 L}\\= 0.497 M[/tex]
Thus, we can conclude that the molar concentration of 29 g of [tex]Mg(OH)_{2}[/tex] dissolved in 1.00 L of water is 0.497 M.
If a gas is at a pressure of 46 mm Hg and temperature of 640 K, what would be the temperature if the pressure was raised to 760 mm Hg?
Answer:
10573.9K
Explanation:
Using pressure law equation;
P1/T1 = P2/T2
Where;
P1 = initial pressure (mmHg)
P2 = final pressure (mmHg)
T1 = initial temperature (K)
T2 = final temperature (K)
According to the information provided in this question,
P1 = 46mmHg
P2 = 760mmHg
T1 = 640K
T2 = ?
Using P1/T1 = P2/T2
46/640 = 760/T2
Cross multiply
640 × 760 = 46 × T2
486400 = 46T2
T2 = 486400 ÷ 46
T2 = 10573.9K
The table below shows some characteristics of three different types of muscles
Answer: Type A are cardiac muscles Type B are skeletal muscles, and Type C are smooth muscles.
Explanation: sub to technoblade :P
PLZZZZZZZZZZZZZZZ HELP IF RIGHT WILL GIVE BRAINLIEST
Answer:
I guess it all of these
as life cycle of an organism can be predicted and yeah it begins with birth hatching or germination for mammals, animals and plants respectively. then it's same for the organism of the same species .
Question:-
Which of the following is true of an organism's life cycle?
Answer:-
It is the same for other organisms of the same species.It is predictableIt begins with birth,hatching or germination.All of these [tex]\checkmark[/tex]
2H2 + O2 2H20
How many moles of oxygen are consumed if 8 moles H2 are used?
Answer:
4 moles of O2 are consumed if 8moles of H2
Calculate the percent composition by mass (to 4 significant figures) of all the elements in calcium phosphate [Ca3(PO4)2], a major component of bone.
Answer:
The elements present in calcium phosphate-based on molecular formula are calcium, phosphorus, and oxygen. The molecular mass of Ca or calcium is 40.08 grams per mole, the molecular mass of P or phosphorus is 30.97 grams per mole, and the molecular mass of oxygen is 16.00 grams per mole. So, in combination, the molecular mass of Ca₃(PO₄)₂ is, = (3 × 40.08 + 2 ×3 0.97 + 8 × 16) = 310.18 grams per mole
Now, the mass percent of calcium is, = n × molecular mass of calcium/ molecular mass of Ca₃(PO₄)₂ × 100% = 3 × 40.08 / 310.18 × 100 = 38.76 % Thus, the mass percent of the calcium in calcium phosphate is 38.76%.
The mass percent of phosphorus (P), = n × molecular mass of phosphorus/molar mass of Ca₃(PO₄)₂ × 100% = 2 × 30.97/310.18 × 100 = 19.97% Thus, the mass percent of phosphorus in calcium phosphate is 19.97%.
The mass percent of oxygen (O), = n × molecular mass of oxygen/molar mass of Ca₃(PO₄)₂ × 100% = 8 × 16/310.18 × 100% = 41.27% Thus, the mass percent of oxygen in calcium phosphate is 41.27%.
Does the addition of a catalyst affect the ΔH of reaction?
Answer:
no
Explanation:
because its just no lol.
students investigating how gravity affects balls of different sizes, is this a good experiment?
Answer:
yea
Explanation:
Answer:1.Owen
2.By dropping the balls from the same height
3.She dropped the balls from different heights
4. Perform a second trial
Explanation: sub to technoblade plz
Based on this chart, which of the following statements describes sources of
energy in the United States?
Sources of Energy
Petroleum
3796
Other
91%
Natural Gas
24%
Renewable
Energy
7%
Coal
2396
*Nuclear
Electric Power
8%
A. Most energy comes from nuclear power and renewable sources.
B. Most energy comes from nonrenewable energy sources.
C. Most energy comes from sources in the solid phase.
D. Most energy comes from greenhouse gases.
Answer:
B. Most energy comes from non-renewable sources
Explanation:
A P E X
In United States Most energy comes from non-renewable energy sources, as petroleum coal and others has the highest consumption in the given chart
What is the energy source in US?In the given chart, the energy consumption in US is based on Petroleum, coal and others the highest consumption pattern as compared to other energy sources
Hence, most energy in the US is from non-renewable energy sources
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Using Equation (10), calculate [Ag+] in the cell, where it is in equilibrium with 1 M Cl- ion. (Ecell in Equation (10) is the negative of the measured value if the polarity is not the same as the standard cell.) Take [Cu2+] to be 1 M. Show your calculations. Ecell=0.4249v, Ecell=-0.00191. M E =E- 0.0592/2 • log ([Cu2+]/[Ag+1?) (10) cell
Answer:
7.16x10⁻⁸M = [Ag+]
Explanation:
Using the equation:
E(Cell) =E⁰ - 0.0592/2 • log ([Cu2+]/[Ag+]²)
Where E⁰= 0.4249V
E(Cell) = -(-0.0019V) -Measured value-
[Cu2+] = 1M
Replacing:
0.0019V = 0.4249V - 0.0592/2 • log (1M/[Ag+]²)
-0.423V = - 0.0296 • log (1M/[Ag+]²)
14.29 = log (1M/[Ag+]²)
1.95x10¹⁴ = 1M / [Ag+]²
[Ag+]² = 5.12x10⁻¹⁵M
7.16x10⁻⁸M = [Ag+]
What will be produced at the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2
Answer:
At the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced
Explanation:
At cathode, reduction reaction takes place.
The dissociation of MgI2 in aqueous solution is Mg2+(aq) and 2I−(aq)
Here, the Iodine reduces to 2I−(aq) from state of 0 (MgI2) to state of -1 (2I−(aq))
Hence, at the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced
Answer:
During electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced at the cathode
Explanation:
Electrolysis is a process whereby ionic compound is broken down or degraded into smaller substances when electric current flow through it.
During electrolysis of magnesium iodide, At the cathode reduction reaction occur .
MgI2 is dissociated to is Mg2+(aq) and 2I−(aq)
Then Iodine is reduced to 2I−(aq) which is 0 in (MgI2) then change to -1 (2I−(aq))
Therefore;
During electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced at the cathode.
A student places 25.0 mL of 0.100 M hydrazoic acid (HN3) in an Erlenmeyer flask and adds indicator. She then adds 5.0 mL of standardized 0.200 M NaOH. What is the pH of the solution
Answer:
pH = 4.42
Explanation:
HN3, a weak acid reacts with NaOH as follows:
HN3 + NaOH → H2O + NaN3
Where 1mol HN3 reacts with 1mol NaOH
After the reaction of only a part of HN3, you will have in solution HN3 (Weak acid) and NaN3 (Conjugate base). This mixture produce a buffer that follows H-H equation:
pH = pKa + log [Conjugate base] / [Weak acid)
Where pH is the pH of the buffer
The hydrazoic acid is a weak acid with pKa = 4.6
And [] could be taken as the moles of each species
After the reaction, the moles of NaOH added = Moles NaN3 produced
And moles HN3 = Initial moles HN3 - Moles NaOH
Moles NaOH = Moles NaN3:
5x10⁻³L * (0.200mol / L) = 1x10⁻³ mol NaN3
Initial moles HN3:
0.025L * (0.100mol / L) = 2.5x10⁻³ moles HN3
final moles: 2.5x10⁻³ moles HN3 - 1x10⁻³ mol = 1.5x10⁻³ moles HN3
Replacing in H-H equation is:
pH = 4.6 + log [1x10⁻³ mol NaN3] / [1.5x10⁻³ moles HN3]
pH = 4.42