Answer:
its 5 got it right
Solution A is a 1.00 L buffer solution that is 1.188 M in acetic acid and 1.188 M in sodium acetate. Acetic acid has a pKa of 4.74. What is the pH change of this solution upon addition of 0.1 mol of HCl? Enter your answer numerically to four decimal places. It will be a negative number.
Answer:
pH change is -0.07
Explanation:
Using H-H equation for acetic acid:
pH = pKa + log [Acetate salt] / [Acetic acid]
Replacing:
pH = 4.74 + log[1.188M] / [1.188M]
pH = 4.74
The HCl reacts with sodium acetate producing acetic acid, thus:
HCl + CH₃COONa → CH₃COOH + NaCl
That means the final moles of sodium acetate are initial moles - moles of HCl and moles of acetic acid are initial moles + moles of HCl.
As the volume of the buffer is 1.0L, initial moles of both substances are 1.188moles. After reaction, the moles are:
sodium acetate: 1.188mol - 0.1mol = 1.088mol
Acetic acid: 1.188mol + 0.1mol = 1.288mol
Using again H-H equation:
pH = 4.74 + log[1.088M] / [1.288M]
pH = 4.67
pH change is: 4.67 - 4.74 = -0.07
The mass of a compound is taken 5 times with the following results: 26.6mg, 26.3mg, 26.2mg, 26.4mg, and 26.1mg. If the true mass is 25.6mg, what is the percent relative error for this set of data? Round to the nearest hundredth of a percent.
Answer:
2.813%
Explanation:
First we must take the average of the five mass measurements
Average value= sum of all five trials/ 5= 26.6 + 26.3 + 26.2 + 26.4 +26.1 /3 = 26.32mg
Now, we have been provided the accurate mass of the compound in the question as 25.6mg
Remember that relative percent error = Average value of measurement - True value of measurement / true value×100
Hence we have;
Percent error=
26.32 - 25.6/25.6 ×100
Percent error= 2.813%
The percentage error is 2.813%
The calculation is as follows:The Average value is
[tex]= (26.6 + 26.3 + 26.2 + 26.4 +26.1)\div 3[/tex]
= 26.32mg
Now the percent error should be
[tex]= 26.32 - 25.6\div 25.6 \times 100[/tex]
= 2.813%
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The correct value according to Ruler A is 2.2cm, whereas the correct value according to Ruler B is 2.27 cm.Perform the mathematical operations indicated by the title of each bin using these two values. Round the correct answers to the appropriate number of significant figures or decimal places. Compare the rounded correct answers with the values given and drag the rounded correct answers to the bin that represents the mathematical operation performed. There are also answers that are not rounded to the correct number of significant figures or decimal places. Drag these answers to the bin named �Incorrect rounding.�For example, multiply the number 2.2 by 2.27. Round the answer to the appropriate number of significant figures. Drag the correctly rounded answer to the bin labeled "2.2 x 2.27"Drag the incorrect answers from the multiplication operation to the bin named "Incorrect rounding."Drag the appropriate items to their respective bins.Item: 5.0 cm^2, 4.994 cm^2, 4.5cm, 0.0cm, 4.47cm, 0.07cm, 0.1cm, 1.0, 1, 1, 10.3, 4.99cm^21. 2.27x2.2 =?2. 2.27/2.2 =?3. 2.27 +2.2 = ?4. 2.27-2.2 = ?5. Incorrect rounding?
Answer:
1) 5.0 cm² ( to two significant figures or one decimal place)
2) 1.0 (to two significant figures or to one decimal place)
3) 4.5 cm ( to two significant figures or one decimal place)
4) 0.1 cm ( to two significant figures or one decimal place)
5) The remaining answers due to incorrect rounding are 4.994 cm², 0.0 cm, 4.47 cm, 0.07 cm, 1, 1.03 cm, 4.99 cm²
Explanation:
The answers given are rounded to two significant figures or one decimal places:
1) 2.27*2.2 = 5.0 cm² ( to one decimal place)
2) 2.27/2.2= 1.0 ( to one decimal place)
3) 2.27+2.2 = 4.5 cm ( to one decimal place)
4) 2.27-2.2 = 0.1 cm ( to one decimal place)
5) The remaining answers due to incorrect rounding are 4.994 cm², 0.0 cm, 4.47 cm, 0.07 cm, 1, 1.03 cm, 4.99 cm²
The number of moles of O2 in 10.6 grams of Na2CO3:
A. 0.1 moles
B. 0.3 moles
C. 0.2 moles
D. None of these
Explain please
u make 1.000 L of an aqueous solution that contains 35.0 g of sucrose (C12H22O11).Part AWhat is the molarity of sucrose in this solution?Express your answer to three significant figures.M
Answer:
0.102 M
Explanation:
Given data
Mass of sucrose (solute): 35.0 gVolume of solution: 1.000 LStep 1: Calculate the moles of solute
The molar mass of sucrose is 342.3 g/mol. The moles corresponding to 35.0 g of sucrose are:
[tex]35.0g \times \frac{1mol}{342.3g} =0.102mol[/tex]
Step 2: Calculate the molarity of sucrose in the solution
The molarity is equal to the moles of solute divided by the liters of solution.
[tex]M=\frac{0.102mol}{1.000L} =0.102 M[/tex]
How can you use a red cabbage solution to determine the ph of a solution
Answer:
(PH color chart at the bottom)
Chop the cabbage into small pieces until you have about 2 cups of chopped cabbage. Place the cabbage in a large beaker or other glass container and add boiling water to cover the cabbage. Allow at least 10 minutes for the color to leach out of the cabbage. Alternatively, you can place about 2 cups of cabbage in a blender, cover it with boiling water, and blend it.
Filter out the plant material to obtain a red-purple-bluish colored liquid. This liquid is at about pH 7. The exact color you get depends on the pH of the water.
Pour about 50–100 mL of your red cabbage indicator into each 250 mL beaker.
Add various household solutions to your indicator until it changes color. Use separate containers for each household solution—you don't want to mix chemicals that don't go well together.
2=Red
4=Purple
6=Violet
8=Blue
10=Blue Green
12 = Green Yellow
It has two substances, muriatic acid and sodium hydroxide. Which of the two substances would you use to unclog the pipes? Please argue your answer.
Answer:
Sodium hydroxide
Out of the two substances, sodium hydroxide would you use to unclog the pipes.
What is the use of sodium hydroxide?Sodium hydroxide is used to produce soaps, rayon, paper, products that explode, dyes, and petroleum products.
The presence of sodium hydroxide in a cleanser or in a homemade aqueous solution converts these pesky fats into soaps and the soap is then easily removed by water.
Hence, out of the two substances, sodium hydroxide would you use to unclog the pipes.
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1. A 99.8 mL sample of a solution that is 12.0% KI by mass (d: 1.093 g/mL) is added to 96.7 mL of another solution that is 14.0% Pb(NO3)2 by mass (d: 1.134 g/mL). How many grams of PbI2 should form?
Pb(NO3)2(aq) + 2 KI(aq) PbI2(s) + 2 KNO3(aq)
Answer:
[tex]m_{PbI_2}=18.2gKI[/tex]
Explanation:
Hello,
In this case, the undergoing chemical reaction is:
[tex]2KI+Pb(NO_3)_2\rightarrow 2KNO_3+PbI_2[/tex]
Thus, we proceed to compute the reacting moles of Pb(NO3)2 and KI, by using the given concentrations and densities and molar masses which are 331.2 g/mol and 166 g/mol respectively:
[tex]n_{Pb(NO_3)_2}=96.7mL*\frac{1.134g}{mL}*\frac{0.14gPb(NO_3)_2}{1g}*\frac{1molPb(NO_3)_2}{331.2gPb(NO_3)_2} =0.0464molPb(NO_3)_2\\\\n_{KI}=99.8mL*\frac{1.093g}{mL}*\frac{0.12gKI}{1g}*\frac{1molKI}{166gKI} =0.0789molKI[/tex]
Next, the 0.0464 moles of Pb(NO3)2 will consume the following moles of KI (consider their 1:2 molar ratio):
[tex]n_{KI}^{consumed\ by\ Pb(NO_3)_2}=0.0464molPb(NO_3)_2*\frac{2molKI}{1molPb(NO_3)_2} =0.0928molKI[/tex]
Hence, as only 0.0789 moles of KI are available, KI is the limiting reactant, therefore the formed grams of PbI2, considering its molar mass of 461.01 g/mol and 2:1 molar ratio, are:
[tex]m_{PbI_2}=0.0789molKI*\frac{1molPbI_2}{2molKI} *\frac{461.01gPbI_2}{1molPbI_2} \\\\m_{PbI_2}=18.2gKI[/tex]
Best regards.
What is the chemical formula for the compound formed between sodium and sulfur?
Answer:
The formula for sodium sulfide is Na2S.
Answer:
NA2S
Explanation:
the compound formed was sodium sulphide
therefore the chemical formula is NA2S
The lava from a volcano can travel up to 100 km/hr if a village is located 3.6 mi from the volcano how many minutes will it take the lava to reach the village
Answer:
3.47 minutes
Explanation:
First we must convert the distance travelled from miles to kilometres
Since ;
1 mile= 1.6093 km
3.6 miles= 3.6 × 1.6093 km = 5.79 Km
Substitute this into
Speed= distance / time
Speed = 100Kmhr-1
Distance= 5.79 Km
Time= the unknown
Time = distance/speed
Time = 5.79/100
Time= 0.0579 hours
Since;
60 minutes make one hour
x minutes make 0.0579 hours
x = 60 × 0.0579 hours
x= 3.47 minutes
4) list 3 protest rights you have that are protected under the law. How can you protect these rights? George Floyd’s ?
Help me please urgent
How many K atoms are there in 5K2CO3?
Select one:
15
10
6
2
Answer:
10
Explanation:
The 5 will multiply the subscript 2 on the K atoms making it 10
What is the color of litmus solution in sodium chloride?
The answer would be blue litmus red
Which part of Dalton's atomic theory was disproved by Thomson's experiment?
O Atoms cannot be created, destroyed, or divided into smaller particles.
O Chemical reactions occur when atoms combine, separate, or rearrange.
O Compounds consist of atoms of different elements combined in simple, whole number ratios.
O All the atoms of an element are the same, but they are different from the atoms of other elements.
The part of Dalton's atomic theory that was disproved by Thomson's experiment is toms cannot be created, destroyed, or divided into smaller particles. The correct option is A.
What is Dalton's atomic theory?According to Dalton's atomic theory, atoms are tiny units of matter that make up all matter, including elements, compounds, and mixtures.
Following are some of the theory's postulates: All substance is made up of atoms, which are exceedingly tiny particles. Atoms belonging to the same element share the same mass and chemical composition.
Thomson presented the plum pudding model of the atom, which contained positively charged "soup" and negatively charged electrons inside.
Thus, the correct option is A. Atoms cannot be created, destroyed, or divided into smaller particles.
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Anne is afraid of lightning, but her father tells her that lightning is good for the soil on their farm. How does lightning help the soil?
O A.
The lightning raises the soil temperature.
OB
OC.
The lightning kills bugs in the soil.
The lightning helps produce oxidized forms of nitrogen such as nitrate.
The lightning sanitizes the water in the soil.
D
O E
The lightning makes the soil more acidic.
Answer:
I think it is...
The lightning helps produce oxidized forms of nitrogen, such as nitrate.
In an ecosystem, the lightning helps produce oxidized forms of nitrogen such as nitrate which nourishes the soil.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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An experiment is set up to determine the type of radioactive decay coming from a certain hazardous nuclide. The analytical instrument used in this experiment detects the charge of the particles emitted from the nuclide. When interpreting the results of the experiment, it was discovered that the emitted particles had no charge at all. Which of the following could be the identity of these particles?A. Positrons
B. Protons
C. γ particles
D. β particles
Answer:
(C.) γ radiation
Explanation:
Gamma radiation, γ , does not consist of particles but a photon of energy. Hence, it has no mass or charge, allowing it to travel much faster than alpha or beta particles.
From the options, only γ-raiation does not have charge as opposed to positrons and protons which are + and beta which is either + or -.
A mountain has a height of 2.74 miles. How high is the mountain in meters? Use the fact that 1 mi=1.609 km .
kkknskndcnndcks
a
Answer:
Explanation:
Rank the following substances in order from most soluble in water to least soluble in water: methane, CH4; 2-butanol, C4H9OH; potassium chloride, KCl; and propane, C3H8. Rank from most to least soluble in water. To rank items as equivalent, overlap them.
Answer:
Arranged in order of most soluble to least soluble in water:
[tex]KCl > CH_{4} > C_{4} H_{9} OH > C_{3}H_{8}[/tex]
Explanation:
Water is a polar solvent due to the electric charge it possesses. Hence it would only dissolve polar molecules.
Non-polar molecules would be dissolved by non-polar solvents.
Short chain alcohols are more soluble than butanol, but generally the polar -OH group is soluble in water.
2 upper N upper o upper c l double-headed arrow 2 upper N upper O (g) plus upper C l subscript 2 (g).
At equilibrium, the concentrations are as follows.
[NOCl] = 1.4 ´ 10–2 M
[NO] = 1.2 ´ 10–3 M
[Cl2] = 2.2 ´ 10–3 M
Answer: The equilibrium constant for the reaction is 0.000016.
Explanation:
Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric coefficients.
The given balanced equilibrium reaction is,
[tex]2NOCl(g)\rightleftharpoons 2NO(g)+Cl_2(g)[/tex]
The expression for equilibrium constant for this reaction will be,
[tex]K_c=\frac{[NO]^2[Cl_2]}{[NOCl]^2}[/tex]
Now put all the given values in this expression, we get :
[tex]K_c=\frac{(1.2\times 10^{-3})^2\times (2.2\times 10^{-3})}{(1.4\times 10^{-2})^2}[/tex]
[tex]K_c=0.000016[/tex]
Thus the equilibrium constant for the reaction is 0.000016.
What would the final salt concentration be if instead of placing the dialysis bag in 4.0 L of distilled water for 12 h, you placed the bag in 1.0 L of distilled water for 6.0 h and then in another 1.0 L of fresh distilled water for another 6.0 h
Answer:chicken
Explanation:There are many types of chicken
Select the statements that correctly describe a buffer. a) An acid added to the buffer solution reacts with the weak base of the buffer. b) The pH of a buffer solution is determined by the ratio of the concentration of conjugate base to the concentration of strong acid. c) A buffer is generally made up of a weak acid and its conjugate base. d) The pH of a buffer solution does not change significantly when any amount of a strong acid is added. e) The Ka of a buffer does not change when any amount of an acid is added to the buffer solution.
Answer:
(B.) The pH of a buffer solution is determined by the ratio of the concentration of conjugate base to the concentration of strong acid.(C.) A buffer is generally made up of a weak acid and its conjugate base. (D.) The pH of a buffer solution does not change significantly when any amount of a strong acid is added.Explanation:
A buffer is solution which resists change in pH upon addition of either acids or bases.
The pH of a buffer is calculated by the ratio of the concentration of base to concentration of acid. The weak acid and conjugate base have a Ka similar to the pH desired.
Statements that are correctly describe a buffer are buffer is generally made up of a weak acid and its conjugate base, pH and Ka of a buffer solution does not change significantly.
What is buffer solution?Buffer solution is a mixture of a weak acid and its conjugate base or weak base with its conjugate acid.
Buffer solutions resists the value of pH of the solution whenever small quantity of strong acid or strong base is added on it. pH of the buffer solution will be calculated by using the Henderson Hasselbalch equation as follow:
For weak acids-
pH = pka + log [conjugate base]/[weak acid]
For weak base-
pH = pka + log [conjugate acid]/[weak base]
Ka is the acid dissociation constant which is not changes too much for the buffer solution.
Hence options (C), (D) and (E) are correct.
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Copper is a solid phase of copper still unknown to science. The only difference between it and ordinary copper is that Copper forms a crystal with a bcc unit cell and a lattice constant . Calculate the density of Copper . Round your answer to significant digits.
Complete Question
The complete question is shown on the first uploaded image
Answer:
The density is [tex]\rho = 8.21479 g/cm^3[/tex]
Explanation:
From the question we are told that
the lattice constant is [tex]a = 0.295 nm = 0.295*10^{-9} = 0.295*10^{-7} cm[/tex]
The density of Copper ([tex]\beta[/tex]) is mathematically represented as
[tex]\rho = \frac{ZM}{a^3N_A}[/tex]
Where Z is the number of units in a unit cell and for BCC crystals Z =2
M is the molar mass of copper which same for Copper with a value of
[tex]M = 63.5 g/mol[/tex]
[tex]N_A[/tex] is the Avogadro's constant with a value of [tex]N_A = 6.022*10^{23}[/tex]
Substituting values
[tex]\rho = \frac{2 *63.5}{(0.295*10^{-7})^3 * (6.022*10^{23})}[/tex]
[tex]\rho = 8.21479 g/cm^3[/tex]
A neutral isotope has 45 neutrons and 36 electrons. Identify the element symbol of this isotope and determine the mass number and number of protons. element symbol: mass number: number of protons:
Answer:
Kr, mass number 81, number protons 36.
Explanation:
If the atom has 36 electrons, and it is neutral, it has 36 protons. 36 protons means that this element has atomic number = 36. This is Kr.
Mass number = number protons + number neutrons = 36 + 45 = 81
1. The symbol of the element is Kr
2. The mass number of the element is 81
3. The proton number of the element is 36
The answer to the question given above, is shown below:
1. Determination of the element symbol.Since the isotope is neutral, it means the atomic number (i.e the proton) and the number of electron are equal.
The isotope has 36 electrons. Therefore, the atomic number is also 36.
Element having atomic number of 36 from the periodic table is Krypton with the symbol of Kr.
2. Determination of the mass number.Neutron = 45
Atomic number = 36
Mass number =?Mass number = atomic number + Neutron
Mass number = 36 + 45
Mass number = 813. Determination of the number protonThe atomic number of an element is simply the proton. Thus,
Atomic number = 36
Proton = Atomic number = 36SUMMARY1. The symbol of the element is Kr
2. The mass number of the element is 81
3. The proton number of the element is 36
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Which of the following changes would increase the pressure of a gas in a closed
container?
a) More gas is added
b) Temperature is increased
c) The container's size is increased
d) Part of the gas is removed
e) Temperature is decreased
f) The container's size is decreased
Answer:
a) More gas is added
b) Temperature is increased
f) The container's size is decreased
Explanation:
For an ideal gas, pressure is jointly proportional to temperature and the quantity of gas, and inversely proportional to the volume. Then pressure will increase for ...
a) More gas is added
b) Temperature is increased
f) The container's size is decreased
At the beginning of the reaction the forward reaction rate is ____ the reverse reaction rate
Answer:
The appropriate answer to the question in the discussion would be "negligible".
Explanation:
Equilibrium specifies "The state in something like a balanced or reversible equation where the frequency including forwarding public response seems to be equal or directly proportional to the rate of the backward process which is defined as the stable equilibrium".Initially, the rate including its reaction seems to be negligible. It's speeding up progressively.So that the above is the right answer.
Answer:
Greater than
Explanation:
Just took it on edge
What element is missing in the following nuclear equation? bismuth radon lead polonium
Answer:
Lead
Explanation:
Lead (Pb) has atomic number 82
Ex Polonium (Po) has atomic number 84 and mass number 212
Answer:
lead
Explanation:
Karla added green pellets to a container of water before she began watering her lawn. What correctly describes
the solvent in her solution.
The green pellets are the solvent because it is dissolved in water.
The water is the solvent because it is dissolved in the green pellets.
The water is the solvent because the green pellets dissolved in it.
The green pellets are the solvent because it dissolved the water.
The correct answer is C. The water is the solvent because the green pellets dissolved in it.
Explanation:
In solutions, the are two substances involved, the solvent and the solute. The solvent is usually a liquid substance; additionally, the solvent dissolves another substance, which is known as the solute. For example, if you dissolve a spoon of salt in a glass of water, the solute is the salt which is the substance dissolved and the solvent is the water because the solute is dissolved in it. According to this, in the case presented the water is the solvent because the green pellets which are the solute dissolve in it.
Which formula represents a salt?
KOH
KCl
CH3OH
CH3COOH
Answer:
kci represents the formula of salt
KCl exists potassium chloride made of potassium and chloride. They are considered salt because they form K+ and Cl- ions, not OH- or H+ ions.
What is meant by chemical equation?
Chemical equations are symbolic depictions of chemical reactions in which the reactants and products are stated in terms of their corresponding chemical formulae.
Chemical equations, which are expressions that list the names and amounts of the chemicals involved in a process, are used to describe chemical reactions. The initial compound(s)—the reactants—and the final compound(s)—the products—are separated by an arrow in a chemical equation.
KCl exists potassium chloride made of potassium and chloride. They are considered salt because they form K+ and Cl- ions, not OH- or H+ ions. Also, they are colorless and taste bitter.Therefore, the correct answer is option b) KCl.
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You are performing an experiment which requires you to add 2.00 grams of benzene to a reaction. Benzene has a density of 0.790 g/mL. You should add:
a. 2.53 mL
b. 0.395 mL
c. 1.58 mL
d. 2.00 mL
Answer:
a. 2.53 mL
Explanation:
Hello,
In this case, by knowing the density is defined as the ratio of the mass to the volume:
[tex]\rho =\frac{m}{V}[/tex]
Since both the mass and density of benzene are given, we can easily compute the volume by solving for it:
[tex]V=\frac{m}{\rho}=\frac{2.00g}{0.790g/mL}\\ \\V=2.53mL[/tex]
Therefore the answer is a. 2.53 mL .
Best regards.
Answer:
a. 2.53 mL
Explanation:
The density is an intensive property, that is, it does not depend on the system size or the amount of material in the system. At a given temperature, the density of a liquid is constant, so it can be used to identify a substance.
The density (ρ) results from the quotient between the mass (m) of the liquid and its volume (V). We can use this expression to find the volume corresponding to 2.00 grams of benzene (ρ = 0.790 g/mL).
ρ = m / V
V = m / ρ
V = 2.00 g / (0.790 g/mL)
V = 2.53 mL
15.00 mL of 0.425 M H2SO4 solution is required to completely react with (neutralize) 23.9 mL
of KOH solution.
What is the
molarity of the KOH solution?
2 KOH(aq) + H2SO4(aq) → K2SO4(aq) + 2 H20 (1)
Answer:
0.533 M KOH
Explanation:
2 KOH(aq) + H2SO4(aq) → K2SO4(aq) + 2 H20 (l}
from reaction 2 mol 1 mol
x 15*10^(-3)*0.425 mol
15.00 mL = 15*10^(-3)L H2SO4 solution
15*10^(-3)L*0.425 mol/L = 15*10^(-3)*0.425 mol H2SO4
x =2*15*10^(-3)*0.425/1 = 2*15*10^(-3)*0.425 mol KOH
23.9mL = 23.9 *10^(-3) L KOH
M(KOH) - molarity KOH
M(KOH)*V(KOH solution) = M(KOH)*23.9 *10^(-3) L KOH - is moles KOH
2*15*10^(-3)*0.425 mol H2SO4 = M(KOH)*23.9 *10^(-3) L KOH
M(KOH) = 2*15*10^(-3)*0.425 /(23.9 *10^(-3)) = 0.533 M