Answer:
pH = 4.89
0.6171g of KOH must be added
Explanation:
Sodium acetate reacts with HCl producing acetic acid as follows:
NaC2H3O2 + HCl → HC2H3O2 + NaCl
That means the moles added of HCl are moles of acetic acid produced and moles of acetate are initial moles - moles of HCl
Moles HCl = Moles acetic acid:
0.204L * (0.452mol / L) = 0.0822 moles acetic acid.
Initial moles sodium acetate:
0.500L * (0.400mol / L) = 0.200 moles
Moles sodium acetate:
0.200 moles - 0.0822 moles = 0.1172 moles sodium acetate
The pH of this buffer (Mixture of a weak acid and its conjugate base) is obtained using H-H equation:
pH = pKa + log [A-] / [HA]
Where pH is pH of the buffer,
pKa is pKa of the buffer (4.74 for acetic acid)
[A-] Moles of sodium acetate -Conjugate base-
And HA moles of acetic acid -Weak acid-
pH = 4.74 + log [0.1172 moles] [0.0822 moles]
pH = 4.89In 0.500L the moles of the buffer are:
0.500L * (0.200moles / 0.704L) = 0.142 moles of buffer
For a pH of 0.15 units more (4.89 + 0.15 = 5.04):
5.04 = 4.74 + log [Acetate] / [Acetic acid]
0.3 = log [Acetate] / [Acetic acid]
1.9953 = [Acetate] / [Acetic acid] (1)
And as:
0.142 = [Acetate] + [Acetic acid] (2)
Replacing (2) in (1):
1.9953 = 0.142 - [Acetic acid] / [Acetic acid]
1.9953 [Acetic acid] = 0.142 - [Acetic acid]
2.9953 [Acetic acid] = 0.142 moles
[Acetic acid] = 0.0474 moles of acetic acid must remain after the addition of KOH.
In the beginning, moles of acetic acid are:
0.0822 moles * (0.500L / 0.704L) = 0.0584 moles.
That means moles added of KOH (Equal to moles of acetic acid that react) are:
0.0584 moles - 0.0474 moles = 0.0110 moles of KOH
In grams (Molar mass KOH = 56.1g/mol):
0.0110 moles KOH * (56.1g/mol) =
0.6171g of KOH must be addedBalance chemical equation hbr(aq)+o2(g) h20(l)+br2(l)
2. Combining 0.242 mol Fe2O3 with excess carbon produced 10.2 g Fe.
Fe2O3+3C⟶2Fe+3CO
(a) Actual yield of Fe mole
(b) percentage mole
(c) theoretical yield of iron mmoles
actual yield = 0.182 mole
theoretical yield : 0.484 mole
percentage mole(% yield)=37.6%
Further explanationPercent yield is the comparison of the amount of product obtained from a reaction with the amount you calculated
General formula:
Percent yield = (Actual yield / theoretical yield )x 100%
An actual yield is the amount of product actually produced by the reaction. A theoretical yield is the amount of product that you calculate from the reaction equation according to the product and reactant coefficients
Reaction
Fe₂O₃+3C⟶2Fe+3CO
a. actual yield of Fe mole
10.2 g produced
[tex]\tt mol~Fe=\dfrac{10.2}{56}=0.182[/tex]
b. percentage mole and theoretical yield
0.242 mol Fe₂O₃ = 2 x 0.242 mol Fe = 0.484 mol (theoretical yield)
percentage yieldpercentage mole)
[tex]\tt \dfrac{0.182}{0.484}=0.376=37.6\%[/tex]
The mass of 900. atoms of sodium(Na)
Answer:
3.44 × 10⁻²⁰ g Na
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
900 atoms Na
Step 2: Identify Conversions
Avogadro's Number
Molar Mass of Na - 22.99 g/mol
Step 3: Convert
[tex]900 \ atoms \ Na(\frac{1 \ mol \ Na}{6.022 \cdot 10^{23} \ atoms \ Na} )(\frac{22.99 \ g \ Na}{1 \ mol \ Na} )[/tex] = 3.4359 × 10⁻²⁰ g Na
Step 4: Check
We are given 3 sig figs. Follow sig fig rules and round.
3.4359 × 10⁻²⁰ g Na ≈ 3.44 × 10⁻²⁰ g Na
Which of the following descriptions best describes a weak base?
A. a base that dissociated completely in water
B. a base that generates a lot of hydroxide ions in water
C. a base that has very low concentration in water
D. A base that dissociates only slightly in water
Answer:
umm.. B. a base that generates a lot of hydroxide ions in water.
The descriptions best describes a weak base is a base that dissociates only slightly in water.
What are bases?Bases are those substances which react with acids to neutralize them, generally bases are the compounds of oxides, hydroxides and carbonates of metal elements.
Bases shows dissocation in the aqueous soluition and pH of bases ranges from 7 to 14. Strong bases shows full dissociation into ions and having higher pH values and weak bases shows partial dissociation into ions & having lower pH values.
Hence, option (D) is correct.
To know more about bases, visit the below link:
https://brainly.com/question/3920636
how does mass and volume affect sinking and floating? Please don't plagiarize....
Answer:
If an object has a higher density than the fluid it is in (fluid can mean liquid or gas), it will sink. If it has a lower density, it will float. Density is determined by an object's mass and volume. If two objects take up the same volume, but have one has more mass, then it also has a higher density.
Explanation:
An electron in the first energy level of the electron cloud has
an electron in the third energy level.
Answer: A LOWER ENERGY
Explanation:
did the test
Answer:
A lower energy!
Explanation:
I know this is not much of an explanation but I took the test i hope you have an amazing day afternoon or night! Hope this helps :3
Please help me please it due today at 11:00am plz help me
Answer:
Point F
Explanation:
Point F is the maximum potential energy.
Point G is lots of kinetic energy.
Point H is low potenital energy and low kinetic energy.
Determine the correct hybridization (from left to right) about each central atom in
CH3CH2OH.
A) 1st C sp3 ; 2nd C sp2 ; O sp B) 1st C sp3 ; 2nd C sp3 ; O sp3
C) 1st C sp ; 2nd C sp2 ; O sp3 D) 1st C sp3 ; 2nd C sp2 ; O sp2
Answer:
B) 1st C sp3 ; 2nd C sp3 ; O sp3
Explanation:
Both carbons in ethanol have an sp³ configuration of their orbitals, given that each carbon atom binds to four other atoms, as can be seen on the extended formula in the attachment.
In these carbons (1st and 2nd) one s orbital and three p orbitals are hybridized to form four hybrid orbitals sp³. These orbitals form four bonds and their bond angles are close to the tetrahedral value of 109.5º,as can be seen for methanol which also has an sp³ configuration.
The oxygen atom can also be described as having sp³ hybrid orbitals. Two of the four hybrid sp³ orbitals in oxygen are occupied by lone electron pairs, and two are used to form bonds with other atoms (in this case the oxygen is bonded to a carbon atom and a hydrogen atom).
Therefore, the three central atoms have an sp³ configuration.
How much work (in JJ) is required to expand the volume of a pump from 0.0 LL to 2.5 LL against an external pressure of 1.1 atmatm
Answer:
- 278.85 J
Explanation:
Given that:
Pressure = 1.1 atm
The initial volume V₁ = 0.0 L
The final volume V₂ = 2.5 L
The work that takes place in a reaction at constant pressure can be expressed by using the equation:
W = P(V₂ - V₁ )
Since the volume of the gas is expanded from 0 to 2.5 L when 1.1 atm pressure is applied. Then, the work can be given by the expression:
W = - P(V₂ - V₁ )
W = -1.1 atm ( 2.5 - 0.0) L
W = -1.1 atm (2.5 L)
W = -2.75 atm L
Recall that:
1 atm L = 101.4 J
Therefore;
-2.75 atm L = ( -2.75 × 101.4 )J
= -278.85 J
Thus, the work required at the chemical reaction when the pressure applied is 1.1 atm = - 278.85 J
A particular reaction has an enthalpy and entropy of reaction of ∆H = +33 kJ/mol and ∆S = +0.15 kJ/mol⋅K. At the three indicated temperatures, determine if either reactants or products are favored?
Answer:
Explanation: check my paage
What is the hybridization state on the central N atom in the azide ion, N3−?
HURRY
Which part of an atom is mostly empty space?
nucleus
proton cloud
electron cloud
neutron
Answer:
Electron cloud
Explanation:
If you were to scale the size of the atom up to have the nucleus be about the size of a basket ball, then the placement of the actual electrons (about the size of a large marble at this scale) throughout the cloud would be many yards away from the nucleus.
Explain how the immune system responds to pathegons
Answer:
The immune system responds to antigens by producing cells that directly attack the pathogen, or by producing special proteins called antibodies. Antibodies attach to an antigen and attract cells that will engulf and destroy the pathogen. The main cells of the immune system are lymphocytes known as B cells and T cells.
Which of the following is an example of a mixture?
A.
calcium
B.
the atmosphere
C.
carbon dioxide
D.
water
Answer:
B. the atmosphere
Explanation:
hope it helps
1) If a bottle of olive oil contains 1.3 kg of olive oil, what is the volume, in milliliters, of the olive oil? Express your answer to two significant figures and include the appropriate units. 2) A cannon ball made of iron has a volume of 116 cm^3. What is the mass, in kilograms, of the cannon ball? Express your answer to three significant figures and include the appropriate units. 3) A balloon filled with helium has a volume of 6.1 L. What is the mass, in grams, of helium in the balloon? Express your answer to two significant figures and include the appropriate units.
Answer:
1) 1.4 × 10³ mL
2) 0.913 kg
3) 1.1 g
Explanation:
1)
Step 1: Calculate the volume of 1.3 kg of olive oil
The density of olive oil is 0.917 kg/L.
1.3 kg × (1 L/0.917 kg) = 1.4 L
Step 2: Convert the volume to mL
We will use the relationship 1 L = 10³ mL.
1.4 L × (10³ mL/1 L) = 1.4 × 10³ mL
2)
Step 1: Calculate the mass of the cannon ball
The density of iron is 7.87 g/cm³.
116 cm³ × 7.87 g/cm³ = 913 g
Step 2: Convert the mass to kg
We will use the relationship 1 kg = 10³ g.
913 g × (1 kg / 10³ g) = 0.913 kg
3)
Step 1: Calculate the mass of the helium in the balloon
The density of balloon is 0.18 g/L.
6.1 L × 0.18 g/L = 1.1 g
An object has a mass of 3.50 grams and a density of 5.61 g/mL. What is the volume of this object? *
Answer:
0.62 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question we have
[tex]volume = \frac{3.50}{5.61} \\ = 0.6238859...[/tex]
We have the final answer as
0.62 mLHope this helps you
What elements in group 17 are solids liquids and gass?
Answer: \(\left( \ce{F} \right)\), chlorine \(\left( \ce{Cl} \right)\), bromine \(\left( \ce{Cl} \right)\), iodine \(\left( \ce{I} \right)\), and astatine \(\left( \ce{At} \right)\)
Explanation:
Whats the answer 50 points and brainliest if its right
Answer:
D
Explanation:
A student wants to use cookies to make a model of the genetic makeup of the offspring of asexual reproduction. He has vanilla cookies and chocolate cookies available. How can he make his model?
A.
Put chocolate cookies in a row with arrows between them showing the progression from parent to offspring.
B.
Use one chocolate cookie parent with arrows showing that it produces vanilla cookies and chocolate cookies as offspring.
C.
Use chocolate cookies and vanilla cookies as the parents, and vanilla cookies and chocolate cookies as the offspring.
D.
Use chocolate cookies and vanilla cookies as parents, and combine half a vanilla cookie and half a chocolate cookie for the offspring.
Answer:
i am not sure but it seems D is the best
Answer:
A
Explanation:
It seems to be the most logical. My reasoning is that for B when it uses one parent cookie that produced genetically different offspring. That is what makes it incorrect. The other two options involve two parents which means that the reproduction would be sexual. A. would be the closest to the answer.
Please let me know if this is correct! Hope it helped.
Which are the three most common gases Giving Brainliest
Answer:
B
Explanation:
i hope this helps
Ice, H2O(s), is classified as: An ionic compound, a molecular compound, a homogeneous mixture, a heterogeneous mixture
Answer:
A molecular compound.
Explanation:
An ionic compound is composed of both metal and non-metal elements. Oxygen and hydrogen are both non-metal elements.Any mixture (no matter if it is homogeneous or heterogeneous) is composed of two or more compounds.Ice is simply water in solid form, so it is only one compound. Hence the answer is A molecular compound.Ice, H2O(s), is classified as ; ( B ) A molecular compound
Given that Ice and H₂O are the same element but in different forms therefore we can classify Ice, H₂O as been a molecular compound.
Ice and H₂O are not ionic compounds because ionic compounds are formed between metal and non-metal elements while H₂O and Ice are neither metals but are both Nonmetals
Hence we can conclude that Ice, H2O(s), is classified as A molecular compound
Learn more : https://brainly.com/question/18158405
Question 1 of 10
In which state of matter do the particles move independently of one another?
A. Amorphous solid
B. Gas
C. Crystalline solid
D. Liquid
Answer:
Gas (B)
Explanation:
a student performed an experiment, using a cocktail peanut, before it was burned the peanut half weighed .353 g. After burning the residue weighed .016 g. The energy released by the conjunction increased the temperature of 200. mL of water in the calorimeter by 7.2 degrees Celsius. Calculate the mass of peanut consumed in the combustion.
2.) Given that the reaction below is a precipitation reaction, what is the missing symbol?
AND
3.) Which of the following would produce a precipitate when mixed water (H20)?
PLZ HELP IM GONNA FAIL THE SEMESTER!!!! I'LL AWARD BRAINLIEST!!
Answer:
2) (s)
3) PbBr2
Explanation:
2) This is a precipitation rxn which means if forms a solid, We use (s) for solid.
3) Refer to solubility table
The sun shines more directly near the equator, bringing more warmth there. In polar regions the sun shines at angles such that
they get little or no sunlight during the winter, causing colder temperatures. Predict how these differences in temperature create a
movement in the atmospheric gases and distribute heat energy from the sun across the planet.
A)
B)
As air in one region diffuses, it becomes less condensed than the
surrounding air and begins to rise and draws more air along.
As air in one region warms, it becomes less dense than the surrounding air
and begins to rise and draws more air in underneath.
As air in one region warms, it becomes less nebulous than the surrounding
air and begins to descend and draws more air in with it.
As air in one region cools, it becomes less compact than the surrounding
air and begins to accelerate and draws more air in supportively.
C)
D)
Answer:Because the Earth is round and not flat, the Sun's rays don't fall evenly on the land and oceans. The Sun shines more directly near the equator bringing these areas more warmth. However, the polar regions are at such an angle to the Sun that they get little or no sunlight during the winter, causing colder temperatures.
Explanation:
Which statement is incorrect?
Acids produce H+ ions when ionized.
B. Bases produce OH^ lons when lonized.
C. Bases are found in the pH range of 1-7 on the pH
scale.
Distilled water has a neutral pH of 7.0.
Answer:
C. Bases are found in the pH range of 1-7 on the pH scale.
Explanation:
Acids are less than 7 on the pH scale, so 1-7. Bases are more than 7 on the pH scale, so 7-14. That's why C is incorrect, hope this helps!
The following concerns the combustion of nitromethane (CH3NO2 - a popular fuel for top-fuel dragsters) according to the reaction below:_______. 2 CH3N02 (1) + ž02(g) → 2C02) + 3H20 (1) + N2(9) a. Burning 121 L of nitromethane at constant pressure releases 1.6 x 100 kJ of energy. What is the enthalpy of combustion of this reaction? The density of nitromethane is 1.16 g/cm². b. Assume you transfer heat involved in the previous problem to 1 kL of water that is initially at 25.0 °C. What is the final temperature of the water?
Answer:
695.8kJ/mol = Enthalpy of combustion
Final temperature = 407.4°C
Explanation:
Taken the reaction:
2CH₃NO₂ + 3/2 O₂ → 2CO₂ + 3H₂O + N₂
The enthalpy of the reaction is the heat released when 1 mole of nitromethane are in combustion.
We need to find the moles presents in 121L of nitromethane using its density and molar mass (61.04g/mol). As these moles releases 1.6x10⁶kJ, we need to find heat released per mole of nitromethane
Mass nitromethane:
121L = 121000cm³ * (1.16g/cm³) = 140360g
Moles:
140360g * (1mol / 61.04g) = 2299.5 moles of nitromethane
Heat released per mole of nitromethane:
1.6x10⁶kJ / 2299.5 mol = 695.8kJ/mol = Enthalpy of combustion
The symbol - is because the heat is released, a + symbol is when the heat is absorbed.
Using:
Q = m×C×ΔT
Where Q is heat (1.6x10⁶kJ = 1.6x10⁹J)
m is mass of water:
1kL = 1000L = 1x10⁶mL = 1x10⁶g
C is specific heat of water: 4.184J/g°C
And ΔT is change in temperature.
Solving for ΔT:
1.6x10⁹J = 1x10⁶g * 4.184J/g°C * ΔT
ΔT = 382.4°C
As initial temperature was 25°C, final temperature is:
382.4°C + 25°C =
407.4°C
From the following heats of reaction,
2C (graphite) + H2 (g) -->C2H2 (g) H = 227 kJ
6C (graphite) + 3H2 (g) -->C6H6 (l) H = 49 kJ
calculate the heat for the reaction
3C2H2 (g) -->C6H6 (l)
A. 26.7 kJ
B. -26.7 kJ
C. -178 kJ
D. 178 kJ
E. -632 kJ
F. 632 kJ
Answer:+178
Explanation:
The heat of the reaction for the following reactions is 178 kJ. the correct option is D.
What is the heat of the reaction?The heat that is added or removed during a chemical reaction is called the heat of reaction.
It is also called the enthalpy of the reaction.
The heat is absorbed or released to maintain the temperature of the reaction.
The enthalpy can be calculated by subtracting the enthalpy of the product from the enthalpy of the reactant.
Thus, the correct option is D.
Learn more about the heat of the reaction
https://brainly.com/question/517776
what is the device to use to measure a potential difference in a circuit called?
Answer:
c. Voltmeter
Explanation:
PLATO LIVES MATTER
What is the mass, in grams, of 2.3 moles of gold?
Answer:
453.031g
Explanation:
atomic mass (molar mass)- 196.97g/m
2.3(196.97)=453.031