Answer:
7.08
Explanation:
To solve this problem we'll use the Henderson-Hasselbach equation:
pH = pka + log[tex]\frac{[A^-]}{[HA]}[/tex]Where [tex]\frac{[A^-]}{[HA]}[/tex] is the ratio of [sodium formate]/[formic acid] and pka is equal to -log(Ka), meaning that:
pka = -log (1.8x10⁻⁴) = 3.74We input the data:
4.59 = 3.74 + log[tex]\frac{[A^-]}{[HA]}[/tex]And solve for [tex]\frac{[A^-]}{[HA]}[/tex]:
0.85 = log[tex]\frac{[A^-]}{[HA]}[/tex][tex]10^{(0.85)}[/tex]=[tex]\frac{[A^-]}{[HA]}[/tex][tex]\frac{[A^-]}{[HA]}[/tex] = 7.08The ratio of [sodium formate] to [formic acid] needed to make the buffer is 7.08
How to determine the pKaEquilibrium constant (Ka) = 1.8×10¯⁴pKa =?pKa = –Log Ka
pKa = –Log 1.8×10¯⁴
pKa = 3.74
How to determine the ratio of [sodium formate] to [formic acid]pH = 4.59pKa = 3.74Ratio of [sodium formate] to [formic acid] =?pH = pKa + Log[sodium formate]/[formic acid]
4.59 = 3.74 + Log[sodium formate]/[formic acid]
Collect like terms
4.59 – 3.74 = Log[sodium formate]/[formic acid]
0.85 = Log[sodium formate]/[formic acid]
Take the anti-log of 0.85
[sodium formate]/[formic acid] = anti-log 0.85
[sodium formate]/[formic acid] = 7.08
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what’s the answer please
Answer:
5 × 10⁻³ mol
Explanation:
Step 1: Given data
Volume of HCl solution (V): 25 cm³Molar concetration of the HCl solution (C): 0.2 mol/dm³Step 2: Convert "V" to dm³
We will use the conversion factor 1 dm³ = 1000 cm³.
25 cm³ × 1 dm³/1000 cm³ = 0.025 dm³
Step 3: Calculate the moles of HCl (n)
We will use the definition of molarity.
C = n/V
n = C × V
n = 0.2 mol/dm³ × 0.025 dm³ = 5 × 10⁻³ mol
1. How many molecules are in 4.5 moles?
Answer:
depends on what molecule you are looking for
Explanation:
In one mole of stuff (atoms, molecules, eggses), there are NA individual items of that stuff. So, there are 4.5 × NA BCl3 molecules; i.e. 4.5 × 6.022×1023 ≅ 27×1023 individual molecules of BCl3
1
Which Element Am I (Core)
Names
1. I have 4 valence electrons and 2 energy levels. Which element am I?
2. Iam in group 16 with 2 energy levels. Which element am I?
3. I am in Period 2 and belong to the same group (family) as silicon. Which element am 1?
4. I have 7 valence electrons and 3 energy levels? Which elementar ?
5. I am in period 3 and I have 12 protons in my nucleus. Which element am 1?
Berr
Sul
ca
3
6
5
6. I am the only element with no neutrons in my nucleus. Which element am 17
6
7. I am the only metalloid with 3 energy levels. Which element am I?
8. I have 1 valence electron and 11 protons, which element am I?
9. Thave only one energy level that is full. Which element am I?
10.1 have 8 valence electrons and I have 4 energy levels. Which element am 1?
10
Answer:
1) Helium
2) Oxygen
3)Carbon
4) Chlorine
5) Magnesium
Explanation:
Helium has the electron arrangement 2, 2. There are two electrons in the first shell and two electrons in the second shell.
Oxygen is the first member of group 16, there are two energy levels in oxygen which are 2,6.
Carbon is in period 2 and is the first member of group 14 (the silicon family).
Chlorine has 7 valence electrons, the electrons are arranged as 2, 8, 7.
Magnesium has 12 protons and 12 electrons. It is the second member of period 3.
A low-pressure weather system comes into the city of Denver. The atmospheric pressure is 693 mmHg.693 mmHg. If 78.0%78.0% of dry air is nitrogen, what is the partial pressure of nitrogen in this low-pressure system?
Answer:
540.54 mmHg
Explanation:
We know that the partial pressure of a substance is defined as; Mole fraction * total pressure.
If the total amount of gases in the atmosphere is 100%, the mole fraction of nitrogen gas is now
78/100 = 0.78
Thus, partial pressure of nitrogen gas = 0.78 * 693 = 540.54 mmHg
it initiates the healing process?
Answer:
platelets?
Explanation:
the question is vauge. but I hope you got it right!
Answer:
Cell division ?
Explanation:
Heart attacks can cause sudden death.
True
False
Answer:
True
Explanation:
2. How many moles are there in 20 grams of Carbon?
Answer:
1.6666666666666 is the ans bcz in each mole there r 12 grams of carbon so the ans is goingtobe 20÷12
According to the mole concept, there are 1.66 moles in 20 grams of carbon.
What is a mole?
Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.
Number of moles is calculated as, mass/molar mass, thus on substitution , number of moles=20/12=1.66 moles.
Thus, there are 1.66 moles in 20 grams of carbon.
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What is the source of most of the salt in the oceans?
human activities adds salt into the ocean
O rivers and streams carry sediment containing salt to the ocean
O marine fish produce salt adding it into the ocean
wind blows the salt into the ocean
What mass of silver nitrate will be needed to react with 125 grams of magnesium chloride?
Answer: m = 4.2 gAgCl
Explanation:
plz need help right away !
Explanation:
1 mole = 6.02 x 10^23 atoms (Avogadro’s number)
Step 1) Determine how many grams of a substance are in the problem
Step 2) Find the amount of grams in 1 mole of the substance
3) Multiply step one by step two
What is the electronegativity and bond polarity like in the "head" vs. the "tail" ends of soap?
Answer:
gay
Explanation:
very gay
HELP ASAP!!! Plzzz
How many total atoms of oxygen are present in the molecules represented here?
Mass number 107 and 61 neutrons
Which planet has these characteristics? - the only planet to have liquid water on its surface - almost three quarters of its surface is covered in water - has a nearly circular orbit
At a certain temperature this reaction follows first-order kinetics with a rate constant of 2.01 s^−1
CICH2CH2Cl (g) → CH2CHCI (g) + HCl(g)
Suppose a vessel contains CICH2CH2Cl at a concentration of 1.34 M. Calculate how long it takes for the concentration CICH2CH2Cl to decrease to 20.0% of its initial value. You may assume no other reaction is important. Round your answer to 2 significant digits.
Answer:
0.80 seconds (2 significant figures)
Explanation:
The equation of the reaction is given as;
CICH2CH2Cl (g) --> CH2CHCI (g) + HCl(g)
Rate constant (k) = 2.01 s^-1
From the units of the rate constant, this is a first order reaction.
Initial Concentration = 1.34 M
t = ?
Final concentration = 20% of 1.34 = 0.268 M
The integrated rate law for a first order reaction is given as;
ln[A] = ln[A]o - kt
ln(0.268) = ln(1.34) - 2.01(t)
-2.01(t) = - 1.6094
t = 0.8007 ≈ 0.80 seconds (2 significant figures)
How many molecules are there in 13.5g of lithium oxide?
please help!
Answer:
the answer is 29.8814
Explanation:
because this is the answer to your question
Cal is titrating 50.8 mL of 0.319 M HBr with 0.337 M Ba(OH)2. How many mL of Ba(OH)2 does Cal need to add to reach the equivalence point?
Answer:
[tex]V_{base}=24.04mL[/tex]
Explanation:
Hello!
In this case, according to the chemical reaction by which HBr reacts with Ba(OH)2:
[tex]2HBr+Ba(OH)_2\rightarrow BaBr_2+2H_2O[/tex]
We can see there is a 2:1 mole ratio between the acid and the base; thus, at the equivalent point we can write:
[tex]2M_{base}V_{base}=M_{acid}V_{acid}[/tex]
Therefore, for is to compute the volume of the used base, we proceed as shown below:
[tex]V_{base}=\frac{M_{acid}V_{acid}}{2M_{base}}[/tex]
And we plug in to obtain:
[tex]V_{base}=\frac{0.319M*50.8mL}{2*0.337M}\\\\V_{base}=24.04mL[/tex]
Best regards!
what volume of copper metal is needed to react with 3.5 moles of silver nitrate
Answer:
3.40 g
Explanation: don't have one :P
How will this system at equilibrium be affected by each of the conditions stated here? 2 Upper H Subscript 2 Baseline (g) + Upper O Subscript 2 Baseline (g) double-headed arrow 2 Upper H Subscript 2 Baseline Upper O (g) + heat. removal of H2O addition of O2 decrease in pressure increase in temperature
Answer:
removal of H2O
✔ System will shift toward the products.
addition of O2
✔ System will shift toward the products.
decrease in pressure
✔ System will shift toward the reactants.
increase in temperature
✔ System will shift toward the reactants.
Explanation:
The reaction Equation :
2H₂ (g) + O₂ (g) ↔ 2H₂O (g) + heat
Answer :
a) Removal of H₂O : The system will move towards the products of the reaction
b) addition of O₂ : The system will move towards the products of the reaction
c) decrease in pressure : The system will tend to move towards the reactants
d) Increase in temperature: The system will tend to move towards the reactants as well
Reason
In an equilibrium reaction changes to reactant components surroundings/conditions in which the reaction is been carried out can cause a significant change in the entire reaction process.
Hence; Removal of H₂O will cause the reaction system to move towards the products also the addition of O₂ will make the equation of the reaction system move towards the product
Decrease in pressure and Increase in temperature causes the equation to move towards the reactants of the reaction
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The definition of symbiotic is
O Having tiny tentacles
O consisting of two oxygen atoms
O having a hard external covering
O living in close association
Answer:
Living in close association
Explanation:
an ionic bond consist of a gas and metal
Answer: yes
Explanation:
Which of these describes a Mole in Chemistry?
A. A counting term for substances
B. The Molar mass of substance in grams
C. 6.02 x 10^23
D. All of the above describe a mole
Answer: D. All of the above describe a mole
Explanation:
Mole is the unit for amount of substance. It is used for describing large number of particles.
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
For example: 1 mole of Na atom will weigh 23 grams and contains [tex]6.023\times 10^{23}[/tex] atoms.
Thus all the above describes a mole.
how does a buffer work?
A. it prevents added acids or bases from dissociating
B. it neutralizes acids or bases by precipitating a salt
C. it forms new conjugate pairs with the added ions
D. it bonds with the added H+ or OH- in solution
Answer:
It bonds with the added H+ or OH in solution.
Explanation:
A) Suppose you separate a 3.02 g mixture of sand and salt. You recover 1.43 g of salt and 1.41 g of sand. What is the percent recovery of the mixture?
B) Suppose you separate a 3.02 g mixture of sand and salt. You recover 1.43 g of salt and 1.41 g of sand. What is the percent recovery of the mixture?
C) Calculate the percent by mass of a solution made from 15 g NaCl (the solute) and 69 g water.
D) What percent of 73.0 g is 26.1 g?
Answer:
A-B) 94 %.
C) 17.9 %.
D) 35.8 %.
Explanation:
Hello!
A-B) In this case, since the total mass of the mixture is 3.02 g and 1.43g+1.41g=2.84 g are recovered in total, we can compute the percent recovery as shown below:
[tex]\%rec=\frac{2.84g}{3.02g}*100\%\\\\\%rec=94\%[/tex]
C) Here, since the solution is made up of NaCl and water, we can say that the mass of the solution is 15g+69g=84g; thus, the percent by mass would be:
[tex]\%=\frac{15g}{84g}*100\%\\\\\%=17.9\%[/tex]
D) In this case, we simply divide 26.1 g by 73.0 g in order to obtain the percent:
[tex]\%=\frac{26.1g}{73.0g}*100\%\\\\\%=35.8\%[/tex]
Best regards!
The percentage in the cases are as follows;
A and B is; 94%C is; 17.9%D is; 35.8%Questions A and B are similar and can be solved as follows;
The total mass of the mixture is 3.02g.The recovered mass = 1.43g + 1.41g = 2.84g% recovery = (2.84/3.02) × 100%% recovery = 94%Question C can be solved as follows;
Total mass of solution = 15 + 69 = 84gMass of solute = 15g% by mass = (15/84) × 100%% by mass = 17.9%Question D can be solved as follows;
% = (26.1/73) × 100%% = 35.8%Read more:
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tion 7
In the beginning of the reaction, A B+C, 2 moles of A are taken, out of which 0.5 moles
gets dissociated. What is the amount of dissociation of A?
(1) 0.5
(2) 1
(3) 0.25
(4) 4.2
What are the main sources of outdoor air pollution and how do they cause smog?
Answer:
The common sources of outdoor air pollution are emissions caused by combustion processes from motor vehicles, solid fuel burning and industry. Other pollution sources include smoke from bushfires, windblown dust, and biogenic emissions from vegetation (pollen and mold spores).
smog is produced when sunlight reacts with nitrogen oxides in the atmosphere. Nitrogen oxides come from car exhaust, coal power plants, and factory emissions. When sunlight hits these chemicals, they form airborne particles and ground-level ozone—or smog.
What is the voltage in a circuit is the current is 3 amps and the resistance is 3 ohms
Answer:
9
Explanation:
V=I*R
3*3
Thats the answer
2. What three states of matter do we see every day?
HELP PLEASEE FAST OMG
Answer:
solid,liquids,gases & plasma
3. Which state of matter has a defined shape?
HELP FAST
Answer:
Solid state of matter has a definite shapeThe answer to this is solids!
Which statement best describes how an electromagnetic motor works?
Electrons are moved through a magnet, creating a current. That current interacts with a circuit, moving the
conductor in the orientation of the field
Electrons are moved through a current, creating a circuit That circuit interacts with a magnet, moving the
conductor in the orientation of the field.
Electrons are moved through a circuit, creating a current That current interacts with a magnet, moving the
conductor in the orientation of the field
Electrons are moved through a magnet, creating a circuit That circuit interacts with a current, moving the
conductor in the orientation of the field
Answer:
Electrons are moved through a magnet, creating a current. That current interacts with a circuit, moving the conductor in the orientation of the field.
Explanation:
Electro magnetic fields are used to create electric current by the movement of electrons. When a coil of wire is wrapped around a magnet it pushes electrons and they flow through a magnet to create current. This current interacts with circuit to move conductor.
