Answer:
pH = 5.35
Explanation:
Given 1.60 grams sodium acetate (NaOAc(aq))*** added to 50ml of 0.10M acetic acid (HOAc(aq)) solution.
Applying common ion effect keeping in mind that the addition of NaOAc provides the common-ion (OAc⁻).
HOAc(aq) ⇄ H⁺(aq) + OAc⁻(aq)
I 0.10m 1.32 x 10⁻³M ≈ ∅M* (1.6g/82.03g/mol) / 0.050L = 0.39M
C -x +x 0.39M + x ≈ 0.39M**
E 0.10M - x x 0.39M
≈ 0.10M
Ka = [H⁺][OAC⁻]/[HOAC] => [H⁺] = Ka·[HOAc] / [OAc⁻]
[H⁺] = (1.75 X 10⁻⁵)(0.10) / (0.39) = 4.5 x 10⁻⁶M
∴ pH = -log[H⁺] = -log(4.5 x 10⁻⁶) = -(-5.35) = 5.35
_______________________________________________
* [H⁺] before adding NaOAc = SqrRt(Ka · [HOAc]) = SqrRt(1.75 x 10⁻⁵· 0.10) = 1.32 x 10⁻³M. Since this concentration value is so small, the initial [H⁺] is assumed to be zero molar (∅M).
** The added [H⁺] is negligible and dropped in the ICE table. That is, adding ~[H⁺] in the order of 10⁻³M does not change the H⁺ ion concentration sufficiently to affect problem outcome and is therefore dropped in the ICE table.
*** Acetic Acid and Sodium Acetate are frequently written HOAc and NaOAc where the OAc⁻ anion is the acetate ion (CH₃COO⁻) for brevity.
The pH of the solution measures the acid of the liquid throughout the molar concentration of hydrogen ions in a solution.
[tex]\bold{CH_3COONa \ mass = 1.60\ g}\\\\[/tex]
Solution Volume (V) [tex]=50.0\ mL =0.05\ L\\\\[/tex]
[tex]\bold{CH3COONa \ molarity =0.10\ M }[/tex]
[tex]\bold{\text{Calculating the CH3COONa moles} =\frac{mass}{molar\ mass}}[/tex]
[tex]= \frac{1.60\ g}{82.03\frac{g}{mol}} \\\\=0.0195\ mol\\\\[/tex]
[tex]\bold{M = \frac{ \text{amount of solute moles} } { \text{solution volume in L} }}[/tex]
[tex]= \frac{0.0195\ mol}{0.05\ L}\\\\ =0.39\ M[/tex]
Using Henderson Hasselbach equation:
[tex]\bold{pH = -\log K_{a} + \log{[salt]}{[acid]}}\\\\[/tex]
[tex]=\bold{ -\log (1.75\times 10^{-5}) + \log ( \frac{0.39}{0.10}) }\\\\=\bold{ 4.757 + \log (3.9)}\\\\=\bold{ 4.757 + 0.5910}\\\\=\bold{ 5.348}\\\\=\bold{ 5.35}\\[/tex]
So, the final answer is "5.35".
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Molecules on the surface of the ice escaping into the water happen in ————.
A. Boiling
B. Freezing
C. Condensation
D. Melting
E. Sublimation
Biological membranes are selectively permeable, allowing certain molecules to cross the membrane, but not others. Classify the molecules or ions depending on how they cross a biological membrane. Note that some of these examples may also utilize active transport to traverse a membrane. However, this question is limited to passive transport processes only. Match the followings with each others
a. Simple Diffusion
b. Facilitated Diffusion
1. steroid hormones
2. K+
3. N2
4. Glucose
Answer:
Following are the solution to these question:
Explanation:
Simple diffusion implies which molecules can move across a cell membrane instead of using the incorporated protein structure channels. Its flow of molecules across these canals is enabled by diffusion. It has steroid hormones and N2.
Facilitated diffusion of molecules via cell membranes, or active transportation, which would be the random mass transit process of molecules or ions via unique cellular membranes from the transmembrane. It has K+ and Glucose.
Which method is most appropriate for finding the age of the earth in years?
a.absolute dating
b.mass number counting
c.atomic number counting
d.radiometric dating
Answer: D
Explanation:
The radioactive dating is also called the radiometric dating. It involves the use of several radioactive substances like Argon, uranium, etc. The correct option is D.
What is radioactive dating?The method of dating rocks and minerals using the radioactive isotopes is defined as the radioactive dating. This method is very helpful to determine the age of igneous and metamorphic rocks which cannot be measured using correlation method.
Many different radioactive isotopes and methods can be used for dating. The elements like uranium and potassium contain a number of different isotopes whose half life is known exactly and thus the concentration of these isotopes within a rock or mineral can measure the age.
The method radiocarbon dating is also used for determining the age of archaeological carbonaceous objects such as wood samples or animal fossils by measuring the radioactivity of ¹⁴C present in them.
Thus the correct option is D.
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2.56 x 10^13 molecules of HgO equates to how many moles of HgO?
Explanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
We have
[tex]n = \frac{2.56 \times {10}^{13} }{6.02 \times {10}^{23} } \\ \\ \\ = 4.25 \times {10}^{ - 11} \: \: \: moles[/tex]
Hope this helps you
A solution contains some or all of the ions Cu2+, Al3+, K+, Ca2+, Ba2+, Pb2+, and NH4+. The following tests were performed, in order, on the solution.
Addition of 6 M HCl produced no reaction.
Addition of H2S with 0.2 M HCl produced a black solid.
Addition of (NH4)2S produced a white solid.
Addition of (NH4)2HPO4 in NH3 produced no reaction.
The final supernatant when heated produced a purple flame.
Identify which of these ions were present in the solution, which were absent, and for which ones no conclusions can be drawn.
Answer:
See explanation
Explanation:
If we look at the tests to be performed on the compounds carefully, we will notice that;
i) Addition of H2S with 0.2 M HCl produced a black solid. This black solid may result from the reaction;
H2S + Cu2+ ---->CuS(balck solid) + H2
or
H2S + Pb2+ ---->PbS(balck solid) + H2
Hence, Cu2+ or Pb2+ may be present
ii) Addition of (NH4)2S produced a white solid. This means that K^+ may be present because the white precipitate is formed during metathesis.
iii) Potassium ion is known to burn with a purple flame.
Hence the suspected ions are;
Cu2+ , Pb2+ and K^+
if eleanor starts with 25.00 ml of a weak acid (the concentration is 0.1084 m), then how many ml of 0.1817 m naoh has to be added to reach the equivalence point
Answer:
14.91 mL
Explanation:
Assuming the weak acid is monoprotic, we can solve this problem using the equation:
C₁V₁=C₂V₂Where subscript 1 stands for the Volume and Concentration of the weak acid, while 2 stands for those of NaOH.
We input the data:
25.00 mL * 0.1084 M = 0.1817 M * V₂And solve for V₂:
V₂ = 14.91 mLThe volume of 0.1817 M NaOH has to be added to reach the equivalence point is 14.91 mL.
How we calculate the volume?Volume for the given solution will be calculated from the below equation:
M₁V₁ = M₂V₂, where
M₁ = Molarity of weak acid = 0.1084 M
V₁ = volume of weak acid = 25 mL
M₂ = molarity of NaOH = 0.1817 M
V₂ = volume of NaOH = to find?
On putting all these values on the above equation and calculate for V₂ as:
V₂ = (0.1084)(25) / (0.1817) = 14.91 mL
Hence required volume is 14.91 mL.
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Given this slope equation, calculate the x-intercept (the point at which y = 0).
y = 0.523x + 16.8
Answer:
The answer is (-31.58, 0) when rounded to 2 decimal places.
what are the two changes of state occurs during distillation
Answer:
The changes of state occur during distillation are boiling followed by condensation. The liquid is converted into its vapor phase at its boiling point and the vapor is then condensed back to liquid on cooling.
Explanation:
Heart me pls
Which substance has the highest ph?
A. Tomato
B. Unpolluted rainwater
C. Ammonium hydroxide
D. Orange juice
Answer:
c ammonium hydroxide nh4oh has higher ph value and its a base
plz mark me branliest
Answer:
c) ammonium hydroxide
Explanation:
ammonium hydroxide nh4oh has higher ph value, and it is an alkaline
The percentage composition of a compound expresses the
amount (by weight) of constituent elements in of the
compound
Answer:
The percentage composition of a compound expresses how much of each element is in the compound.
How many liters of nitrogen gas (N₂) are required to produce 7.5 x 10²⁶ molec NH₃ gas with excess of hydrogen gas at STP?
Answer: The volume of nitrogen gas that is required is 13944 L.
Explanation:
Given values:
Number of molecules of ammonia gas = [tex]7.5\times 10^{26}[/tex]
According to the mole concept:
[tex]6.022\times 10^{23}[/tex] number of molecules are present in 1 mole of a compound
So, [tex]7.5\times 10^{26}[/tex] number of molecules will be present in [tex]\frac{1}{6.022\times 10^{23}}\times 7.5\times 10^{26}=1.245\times 10^3 moles[/tex] of ammonia gas
The chemical equation for the formation of ammonia gas follows:
[tex]N_2 (g) + 3H_2(g) \rightarrow 2NH_3(g)[/tex]
According to the stoichiometry of the reaction:
2 moles of ammonia gas are produced from 1 mole of nitrogen gas
So, [tex]1.245\times 10^3[/tex] moles of ammonia gas will be produced from [tex]\frac{1}{2}\times 1.245 \times 10^3=6.225\times 10^2[/tex] moles of nitrogen gas
At STP conditions:
1 mole of a gas occupies 22.4 L of volume
So, [tex]6.225 \times 10^2[/tex] moles of nitrogen gas will occupy [tex]\frac{22.4 L}{1 mol}\times 6.225\times 10^2 moles=13944 L[/tex] of volume
Hence, the volume of nitrogen gas that is required is 13944 L.
When 4.088 grams of a hydrocarbon, CxHy, were burned in a combustion analysis apparatus, 13.82 grams of CO2 and 2.829 grams of H2O were produced.
In a separate experiment, the molecular weight of the compound was found to be 78.11 amu. Determine the empirical formula and the molecular formula of the hydrocarbon.
Answer:
Empirical formula: CH
Molecular formula: C₆H₆
Explanation:
Based on the combustion of a hydrocarbon, the moles of CO₂ = Moles of Carbon in the hydrocarbon and the moles of H₂O = 1/2 moles of hydrogen in the hydrocarbon.
The empirical formula is the simplest whole number of atoms present in a molecule. With the moles of C and H we can find empirical formula:
Moles C -Molar mass CO₂ = 44.01g/mol-:
13.82g * (1mol / 44.01g) = 0.314 moles C
Moles H -Molar mass H₂O = 18.01g/mol-:
2.829g H₂O * (1mol / 18.01g) = 0.157 moles H₂O * (2mol H / 1mol H₂O) = 0.314 moles of H
The ratio of moles H: moles C:
0.314 moles / 0.314 moles = 1
That means empirical formula is:
CHWith the molecular weight and empirical formula we can find the molecular formula:
Molar mass CH = 12.01g/mol+1.01g/mol = 13.02g/mol
As the molecular weight of the molecule is 78.11amu = 78.11g/mol, there are:
78.11g/mol / 13.02g/mol = 6 times the empirical formula in the molecular formula
That means molecular formula is:
C₆H₆When a thermometer is heated, the red liquid inside the thermometer moves up. This is mainly because:
A. The red liquid is thin.
B. The molecules of the liquid move faster and get a little further apart.
C. Hot liquid is lighter.
D. The glass of the thermometer gets hot.
The thermometers with red liquid usually depicts a kerosene based column with red dye. It is more safe than mercury thermometer. The red liquid inside the thermometer moves up due to the molecules of the liquid move faster and get a little further apart. The correct option is B.
What is thermometer?The device which is used to measure the temperature is defined as the thermometer. It can measure the temperature of a solid such as food, a liquid like water and a gas like air.
The thermometers which are developed for clinical purposes are called clinical thermometers. It can also measure the temperature of human body. It is a long narrow glass tube which contain a bulb and consists of mercury at the end.
When a thermometer is heated, the molecules present in the liquid inside the thermometer get a little further apart. Because the liquid takes up more space. So the red line moves up in the tube.
Thus the correct option is B.
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3. Jordan built a model of a neutral helium atom.
Nucleus
Proton
Neutron
Electron
What change would fix the mistake in Jordan's model?
Look at the diagram of a fuel cell below.
Which part of the fuel cell does A represent?
A. air
B. anode
C. cathode
D. electrolyte
Answer:
It is a electrolyte.
Explanation:
I took the test.
It represents an electrolyte.
What happens if electrolytes are low in the body?
A level under three can cause muscle weakness, spasms, cramps, paralysis, and respiratory problems. If it continues, kidney problems may occur.
What do electrolytes do for your body?Electrolytes are substances that have a natural positive or negative electrical charge when dissolved in water. They help your body regulate chemical reactions, maintain the balance between fluids inside and outside your cells, and more.
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If 45 grams of solid aluminum and 301 grams of ammonium perchlorate are reacted. How much excess reactant is left over? Show your work using equation editor.
Answer: Your balanced equation is 2Al + 3S --> Al_2S_3. In two separate equations, first use the 48.5g of Al to find the amount (in moles) of Al_2S_3. Then use the 62.8g of S to find the amount (in moles) of Al_2S_3. By doing these, you find which reactant (the Al or the S) produces the least amount of Al_2S_3. Since it's the S, that's the limiting reactant: you then use that 62.8g of S to find how many grams of Al will be used in the reaction. (Use the same balanced equation.) You find that 35.2g of Al will be used, then find the excess by subtracting that 35.19 from the original 48.5g. Your excess amount is 13.3g of Al!
Explanation:
hopefully this is what you were looking for <3 :)
The amount of excess reactant that left over the chemical reaction between aluminum and ammonium perchlorate is 0.9 moles.
How do we convert mass into moles?Mass into moles (n) will be converted by using the below equation as:
n = W/M, where
W = given mass
M = molar mass
Moles of 45g of Aluminum = 45g / 27g/mol = 1.66 mol
Moles of 301g of ammonium perchlorate = 301g / 117.4g/mol = 2.56 mol
Both reactants are reacted with each other and one of the reactant is fully consumed, so the excess reactant will be calculated as:
Excess reactant = 2.56mol - 1.66mol = 0.9 moles
Hence amount of excess reactant is 0.9 moles.
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Identify the reactants and products in the following chemical equation: Zn +2HCl --> ZnCl2 + H2 *
20 points
A: Reactants: Zn & HCl Products: ZnCl2 & H2
B: Reactants: ZnCl2 & H2 Products: Zn & HCl
C: Reactants: Zn & H2 Products: ZnCl2 & HCl
Answer:
A.
Explanation:
zinc and hydrochloric acid reacts to form zinc chloride and hydrogen.
hope it helps. :)
Calculate the percent mass of hydrogen in ethane (C2H6).
Answer:
80.% carbon and 20.% hydrogen
Explanation:
Ethane has molecular formula C2H6. So What is the composition of carbon and hydrogen in ethane. its alot to explain but yea thats wht i got
An inventor claims to have developed a new perfume that lasts a long time because it doesn't evaporate. Comment on this claim.
a. This would be impossible to make because the perfume would have to be pressurized in order to not evaporate.
b. This product is sure sweep the market making many happy customers.
c. In order to smell something, the molecules must evaporate and reach your nose. If the new perfume doesn't evaporate, it will not have an odor.
d. A perfume that does not evaporate could be toxic since the molecules never leave the skin.
Answer:
C
Explanation:
Perfume needs to evaporate in order to smell. If this perfume didn't evaporate, it would stay as a liquid and never smell.
It wouldn't be D, as no toxic perfumes is sold.
It's not A because perfume doesn't have to be pressurized in order to not evaporate.
It's not B, as it is a hasty conclusion to the claim. Plus, if the perfume did have an odor, even while not evaporating, the sales would be low as the product is that good.
Hhheppppp fffaaast
Mixture of water and LEAD SULPHATE is an example of Homogeneous mixture Select one : True O False
Answer:
False
Explanation:
Lead sulfate is insoluble in water and sinks in water
(sorry if it's wrong)
What is the main difference between rain and hail?
Answer:
Rain is a liquid and hail is a solid.
If there is sufficient water in the reaction system, how many grams of KOH can be produced from 22.2 g of K?
Answer: 31.9 g of KOH can be produced from 22.2 g of KOH
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} K=\frac{22.2g}{39g/mol}=0.57moles[/tex]
[tex]2K+2H_2O\rightarrow 2KOH+H_2[/tex]
According to stoichiometry :
2 moles of [tex]K[/tex] produce = 2 moles of [tex]KOH[/tex]
Thus 0.57 moles of [tex]K[/tex] will produce=[tex]\frac{2}{2}\times 0.57=0.57moles[/tex] of [tex]KOH[/tex]
Mass of [tex]KOH=moles\times {\text {Molar mass}}=0.57moles\times 56g/mol=31.9g[/tex]
Thus 31.9 g of KOH can be produced from 22.2 g of KOH
Our most recent mass extension happened about 65million years ago. Describe the effects of this event.
Answer:
To explain what caused this mass extinction, scientists have focused on events that would have altered our planet's climate in dramatic, powerful ways. The leading theory is that a huge asteroid or comet slammed into Earth 65 million years ago, blocking sunlight, changing the climate and setting off global wildfires.
Is anyone good at chemistry if so can someone help me please ?
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In general, salts (formed during a neutralization reaction) are ionic compounds that are soluble in water and dissociate in solution into ions that conduct electricity. Out of the six statements given, there are three related statements that rehash the foregoing, and there are three related statements that are collectively incorrect.
Statements A, B, and D are (generally) true regarding salts formed during a neutralization reaction. When you consider that the net ionic equation of many acid-base neutralization reactions is H⁺(aq) + OH⁻(aq) → H₂O(l), the counterions of the H⁺(aq) and OH⁻(aq) are the aqueous spectator ions that comprise the salt. These ions are electrolytes, as they are charged species that can carry a current in solution; they are ionic compounds by definition since they're composed of cations and anions; and, as aqueous species, they're clearly dissolved in water.
Statements C, E, and F, as a whole, generally aren't true of such salts.
What is the IUPAC name for the compound shown?
Based on this information which of the following conclusions can be drawn about the growth rate of grass? hurry
2. A plant growing in response to the sunlight.
Gravitropism
Phototropism
Thigmotropism
Hydrotropism
Answer:
Phototropism.
Explanation:
Phototropism is the phenomenon of plants growing in response to light. This is a response to the plants to align or steer towards the source of sunlight, thereby becoming the 'path' to their growth.
The term "photo" means light and "tropism" means "growth" or movement towards". So, we can safely say that phototropism is the scientific and natural phenomenon of plants growing towards or in response to the sunlight.
Thus, the correct answer is phototropism.
5. Element X exists as diatomic molecules.
In which group of the Periodic
Table is X placed?
A. Group O
B.
Group I
C.
Group II
D.
Group VII
Element X Exists as diatomic molecules . In which group of the Periodic Table is X placed ?
Group VII
Group VII - elements are Fluorine , Chlorine , Bromine and Iodine .
They exist in diatomic molecules as F2 , Cl2 , Br2 and I2 .
Which material is likely to slow the flow of electric charges the most? Explain.
Answer:
copper hiiiiiiiiiiiii
Give the systematic (IUPAC) name for each molecule. This molecule has the condensed formula C H 3 C O C H 3. The oxygen atom has a double bond to the center carbon. systematic (IUPAC) name: This molecule has the condensed formula C H 3 C H 2 C H 2 C O C H 3. The oxygen atom has a double bond to carbon. systematic (IUPAC) name:
Answer: The IUPAC name of [tex]CH_3COCH_3[/tex] propan-2-one and [tex]CH_3CH_2CH_2COCH_3[/tex] is pentan-2-one.
Explanation:
The basic rules for naming of organic compounds are :
1. First select the longest possible carbon chain. The longest possible carbon chain should include the carbons of double or triple bonds or functional group.For the number of carbon atom, we add prefix as 'meth' for 1, 'eth' for 2, 'prop' for 3, 'but' for 4, 'pent' for 5, 'hex' for 6, 'sept' for 7, 'oct' for 8, 'nona' for 9 and 'deca' for 10.
2. The naming of alkane is done by adding the suffix -ane, alkene by adding the suffix -ene, alkyne by adding the suffix -yne and ketones by adding the suffix -one.;
3. The numbering is done in such a way that the carbon containing the functional group gets the lowest number. While writing the name, the word root is given first , followed by the position of carbon containing the functional group followed by the suffix.
The IUPAC name of [tex]CH_3COCH_3[/tex] propan-2-one and [tex]CH_3CH_2CH_2COCH_3[/tex] is pentan-2-one.