Answer:
3.11 is the pH of the buffer
Explanation:
The pH of a buffer is obtained using H-H equation:
pH = pKa + log [Conjugate base] / [Weak acid]
Where pH is the pH of the buffer, pKa = -log Ka = 3.14 for the citric buffer and [] could be taken as the moles of each species.
The citric acid,HX (Weak acid), reacts with NaOH to produce sodium citrate, NaX (weak base) and water:
HX + NaOH → H2O + NaX
That means the moles of NaOH added = Moles of sodium citrate produced
And the resulitng moles of HX = Initial moles - Moles NaOH added
Moles HX and NaX:
Moles NaOH = 0.100L * (0.65mol / L) = 0.065 moles NaOH = Moles NaX
Moles HX = 0.300L * (0.45mol / L) = 0.135 moles HX - 0.065 moles NaOH = 0.070 moles HX
Replacing in H-H equation:
pH = 3.14 + log [0.065mol] / [0.070mol]
pH = 3.11 is the pH of the buffer
What volume of chlorine gas at 27 °C, 812 mmHg, is required to react with an excess of carbon disulfide so that 5.00kJ of heat is evolved?
Answer:
The correct answer is 1.21 L.
Explanation:
Based on the given information, the reaction will be,
CS2 (l) + 3Cl2 (g) ⇒ CCl4 (l) + S2Cl2 (l)
By using the standard values of the substances, the standard enthalpy of the reaction is,
ΔH° = [(-139.5) + (-58.5) – 0 – (87.3)] kJ/mol
= -285.3 kJ/mol
The amount of heat evolved for 3 moles of chlorine reacted us 285.3 kJ.
Now the number of moles of chlorine needed to react to produce 5.00 kJ is,
= 5.00 kJ × 3 mol Cl2/285.3 kJ
= 0.0526 mol Cl2
Now the volume of chlorine gas at 27degree C and 812 mmHg will be,
Volume = 0.0526 mol Cl2 × 0.0821 Latm/mol K × 300 K/ 1.07 atm
= 1.21 L
define perodic table what are period and groups
Answer:
period is a horizontal row of the periodic table. There are seven periods in the periodic table, with each one beginning at the far left.
Explanation:
maaf kalo salah
In model periodic table the atoms are arranged wrt atomic number, there chemical behaviour, and properties.
The horizontal rows of periodic table are known as periods.
The vertical line of periodic table are knows as groups.
I have added 15 L of air to a balloon at sea level (1.0 atm). If I take the balloon with me
to Denver, where the air pressure is 0.85 atm, what will the new volume of the balloon
be?
Answer:17.65 or 18 L
Explanation:
How many moles of SO2 will be produced from 11.5 moles of O2?
Explanation:
Respuesta: La masa atómica del carbono (C) es 12 g/mol; para el oxígeno (O) es de 16 g/mol. Esto significa que 6.022 x 1023 átomos de carbono pesan 12 gramos. Según esto, el peso molecular del CO2 es: 12 g/mol [C] + 2 x 16 g/mol [O2] = 44 g/mol
When you test starch with Barfoed’s reagent, what would be the answer, positive or negative?
Answer:
It would test positive.
Examples of a chemical reaction?
Answer:
Decomposition of normal salt ( sodium chloride )
Formation of water from hydrogen peroxide.
Combustion of propane
e.t.c
8. What was the original concentration in the BHL sample, if the dilution is 1:500 and the concentration 0.07 mg/ml
Answer:
The original concentration is "35 mg/ml".
Explanation:
According to the question,
The solution is diluted,
= 1:50
The initial volume,
V1 = 1 ml
Final concentration,
= 0.07 mg
then,
The final volume,
V2 = 500 ml
As we know,
⇒ [tex]V_1N_1=V_2N_2[/tex]
or,
⇒ [tex]N_1=\frac{V_2N_2}{V_1}[/tex]
On substituting the values, we get
⇒ [tex]=\frac{500\times 0.07}{1}[/tex]
⇒ [tex]=\frac{35}{1}[/tex]
⇒ [tex]=35 \ mg/ml[/tex]
A 0.07 mg/mL BHL solution was prepared by performing a 1:500 dilution on a 35 mg/mL solution.
A 1:500 dilution was carried out to prepare a 0.07 mg/mL BHL solution. We can find the concentration of the initial solution using the dilution rule.
What is the dilution rule?It is an equation that relates the concentration and volume of a concentrated and a dilute solution. The mathematical expression is:
C₁ × V₁ = C₂ × V₂
where,
C₁ is the concentration of the concentrated solution.V₁ is the volume of the concentrated solution.C₂ is the concentration of the dilute solution.V₂ is the volume of the dilute solution.C₁ = C₂ × (V₂/V₁)
C₁ = 0.07 mg/mL × (500/1) = 35 mg/mL
A 0.07 mg/mL BHL solution was prepared by performing a 1:500 dilution on a 35 mg/mL solution.
Learn more about dilution here: https://brainly.com/question/1615979
From the following data ,determine of formation for diborane(B2H2(g), at 25
B2H2(g) 3O2(g)(B2O3(S)3H2O(g) ,=-1941kJ
2B(s) O2(g) (B2O3(s) ,=-2368 kJ
H2(g) O2(g) (H2O(g) , =-241.8 kJ
What does the reproductive system control?
How many dots are drawn in a Lewis dot structure for elements in group 2 of the periodic table?
1 becasuevof one vvalence shell
Explain why this combination of compounds can or cannot make a buffer solution. Hint: apply definition of a buffer, mechanism of its action and consider whether the compound is acid (weak/strong) or base (weak/strong). HF (0.2 mol) and NaOH (0.1 mol)
Answer:
This combination can make a buffer
Explanation:
A buffer is defined as an aqueous mixture of a weak acid and its conjugate base, or vice versa.
In the problem, HF is a weak acid, and its conjugate base is F⁻.
When NaOH reacts with HF, F⁻, Na⁺ and H₂O are produced as follows:
NaOH + HF → F⁻ + Na⁺ + H₂O
As there are initially 0.2mol of HF and 0.1mol NaOH, after the reaction you will have:
0.1mol HF and 0.1mol F⁻. As both, the weak acic and the conjugate base are present:
This combination can make a bufferhelp me pls i really need help
Answer:
Veins
Explanation:
Veins carry blood to the heart while arteries carry away from the heart
1. What is the relationship between pressure and volume?
Answer:
An increase in pressure would cause less volume and vice versa. They are inversely proportional.
Explanation:
This is due to Boyle's Law (and because an increase in pressure would increase the force on the container, however, if it's a closed container, it would burst)
Feel free to mark it as brainliest :D
A chemist adds 255 .0 mL of a M copper(II) sulfate solution to a reaction flask. Calculate the mass in grams of copper(II) sulfate the chemist has added to the flask. Round your answer to significant digits.
Answer:
The correct answer is 40.7 grams.
Explanation:
Based on the given information, the volume of copper sulfate added to the solution is 255 ml or 0.255 L. The molarity of copper sulfate is not given, so let us consider it to be 1 M, which can also be written as 1 moles per liter.
The moles of copper sulfate can be determined by using the formula,
Moles = Molarity * Volume in Liters
Moles of CuSO4 = 1 moles/Liter * 0.255 L
Moles of CuSO4 = 0.255 moles
The mass of CuSO4 added in the solution will be,
Mass of CuSO4 = Moles * Molecular mass
= 0.255 moles * 159.609 grams per mole
= 40.7 grams.
Pick the correct statement about the pure water. Group of answer choices Pure water contains no ions. Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O ] ions. Pure water contains larger amounts of hydroxide [OH-] than hydronium [H3O ] ions. Pure water is an electrolyte. Pure water contains smaller amounts of hydroxide [OH-] than hydronium [H3O ] ions.
Answer:
Pure water contains no ions. TRUE
Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O+ ] ions. TRUE
Explanation:
This is the equilibrium for pure water:
2H₂O ⇄ H₃O⁺ + OH⁻ Kw
We see that pure water has no Ions. Pure water can not conduct electricity.
Generally ionized water comes from the water tap.
Another feature of pure water is pH.
Definetely pH of pure water is : 7
As pH = 7, [H₃O⁺] = 1×10⁻⁷
Then, [OH⁻] = 1×10⁻⁷
This is reazonable because Kw is 1×10⁻¹⁴ and Kw = [H₃O⁺] . [OH⁻]
In conclussion:
Pure water contains no ions. TRUE
Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O+ ] ions. TRUE
Pure water contains larger amounts of hydroxide [OH-] than hydronium [H3O+] ions. FALSE
Pure water is an electrolyte. FALSE
Pure water contains smaller amounts of hydroxide [OH-] than hydronium [H3O ] ions. FALSE
A plastic rod that have just been rubbed with a fur and kept near a negatively charged ballon that is freely suspended. The charged balloon moves away from the plastic. What does this explain you ?
Explanation:
that both the plastic & balloon have the same charge
What is predicted to happen if the permafrost in the Arctic melts?
Answer: It is causing erosion, landslides, and craters. If this keeps up the ice in the artic will eventually be gone
Explanation:
Hdhduhdhdudbbdhhdhdhdhdjjdhdhduuxhxuxuxuxuux
Answer:
dfdgfhgjghfdgsfdaafsgdhfjgkfjdgsasfdgfhghjgfdsafg
im 100% sure
Explanation:
I dont understand this
Answer:
me too
Explanation:
does anyone know this??
Answer: C2H6O
Explanation: It is C2H6O with a molar mass of 46.07 g/mol.
Describe how to test your unknown salt mixture for the presence of
Na3PO4.12H2O.
Na3PO4*12H2O + BaCl2*2H2O = Ba3(PO4)2 + NaCl + H2O
add barium chloride to your Na3PO4.12H2O a white precipitate of Ba3(PO4)2 will be formed wrt salt(NaCl) and water(H20) if Na3PO4.12H2O. will be there.
When water and alcohol are mixed, the final volume is less than the total of volume of alcohol plus water added due to .......
Answer:
molecules take up more space
BRAINIEST AND POINTS
Which option below accurately describes the relationship between frequency and energy level?
A. Higher frequency means higher energy level.
B. Lower frequency means higher energy level.
13. Which of the following correctly provides the names and formulas of polyatomic ions?
chromate: Cro42 -; dichromate: Cr2O7 2 -
O nitrite: NO -; nitrate: NO2
sulfite: S 2-; sulfate: SO3
O carbonate: HCO3 -; bicarbonate: C03
A 15.67 g sample of a hydrate of magnesium carbonate was heated, without decomposing the carbonate, to drive off the water. The mass was reduced to 7.58 g. What is the name of the hydrate
Answer:
The correct answer is MgCO₃.5H₂O.
Explanation:
Based on the given information,
The mass of hydrate of magnesium carbonate given is 15.67 grams, and the mass of anhydrous magnesium carbonate given is 7.58 grams.
Now the mass of water will be,
= 15.67 grams – 7.58 grams
= 8.09 grams
The molecular mass of magnesium carbonate is 84.32 grams, the moles of MgCO₃ can be determined by using the formula,
Number of moles = Mass/Molecular mass
Moles of MgCO₃ = 7.58/84.32
= 0.0898 moles
Similarly, the number of moles of water will be,
Moles of H₂O = 8.099/18.02
= 0.4489 moles
After getting the values, there is a need to choose the smaller value and use it to divide both the values to get the ratio,
MgCO₃ = 0.0898/0.0898 = 1
H₂O = 0.4489/0.0898 = 4.9 or 5
Thus, the molecular formula for the hydrate will be MgCO₃.5H₂O.
A metal has a mass of 35.4 g and volume 3.11 ml. Find the density of this metal
Answer:
11.4
Explanation:
Density = Mass / Volume
Density = 35.4 / 3.11
Density = 11.38263666
As there are more number of digits after the decimal, you can round it to 3 significant figure.
Now, your value will be:
Density = 11.4
NO LINKS PLEASE
1. What are the reactants at the start of this chemical reaction? What do you start with?
2. What are the products at the end of this chemical reaction? What do you end with?
3. If the total mass of the reactants equals 150 grams, what would the total mass of the
products be?
Answer:
1.The substance(s) to the left of the arrow in a chemical equation are called reactants. A reactant is a substance that is present at the start of a chemical reaction. The substance(s) to the right of the arrow are called products
2.The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products
3.The law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. For example, the mass of sodium plus the mass of chlorine that reacts with the sodium equals the mass of the product sodium chloride.
How many moles of solute are in a 1.50 M solution of HCl with a volume of 7.98 liters?
Answer:
[tex]\boxed {\boxed {\sf x\approx 12.0 \ moles \ HCl}}[/tex]
Explanation:
Molarity is a measure of concentration in moles per liter.
[tex]molarity= \frac{moles \ of \ solute}{liters \ of solution}[/tex]
We know the solution has a volume of 7.98 liters and it has a molarity of 1.50 M HCl.
1 molar (M) is 1 mole per liter, so the molarity is also 1.50 moles of HCl per liter.We know 2 values for the variables, but the value for moles of solute is unknown, so we use x.
molarity= 1.50 mol HCl/L moles of solute=xliters of solution = 7.98 LSubstitute the values into the formula.
[tex]1.50 \ mol \ HCl/L=\frac{x}{7.98 \ L}[/tex]
We are trying to solve for x, the moles of solute, so we must isolate the variable. It is being divided by 7.98 liters and the inverse of division is multiplication. Multiply both sides of the equation by 7.98 liters.
[tex]7.98 \ L *1.50 \ mol \ HCl/L=\frac{x}{7.98 \ L} * 7.98 \ L[/tex]
[tex]7.98 \ L *1.50 \ mol \ HCl/L=x[/tex]
The units of liters (L) cancel each other out.
[tex]7.98 *1.50 \ mol \ HCl=x[/tex]
[tex]11.97 \ mol \ HCl=x[/tex]
The original measurements of molarity and volume both have 3 significant figures, so our answer must have the same. For the number we found, that is the tenths place.
The 9 in the hundredth place tells us to round the 1 to a 2. We leave a 0 in the tenths place to ensure there are 3 significant figures.
[tex]12.0 \ mol \ HCl \approx x[/tex]
There are approximately 12.0 moles of solute in the solution.
How many grams of ammonium fluoride, , must be dissolved to prepare 300. mL of a 0.234 M aqueous solution of the salt
Answer:
24.24 g
Explanation:
First we calculate how many moles are there in 300 mL of a 0.234 M solution, using the definition of molarity:
Molarity = moles / litersConverting 300 mL to L ⇒ 300 mL / 1000 = 0.300 L
0.234 M = moles / 0.300 Lmoles = 0.78 molesThen we convert 0.78 moles of NH₄F into grams, using its molar mass:
0.78 mol * 31.073 g/mol = 24.24 gplease answer all three of these questions
Answer:
I think it's 1.D
2.C
3.C
my apologies if it's incorrect