CaseAnswer:
-Mole of stearic acid used = 1.3*10^-3 mol
-Molecules of stearic acid there would be in 1 mole of stearic acid = 7.994*10^20 molecules
Explanation:
Know information from the problem are:
Mass concentration of C18H32O2 = 1.6x10^-4 g/ml, Molar mass of C18H32O2 = 284 g/mol.
Unit factor from drops to ml is 72 drops = 1ml. Therefore, for every drop, n, given, there would be n drops (1ml/ 72drops). The problem tells that stearic acid was added to hexane and that the addition process was done three-time with different amounts of drops. Think of this as releasing a substance from a burette during titration. If we convert the drops into millimeters, we would have 20 drops (1ml/72drops)= 0.28 ml, 21 drops (1ml/72drops)= 0.29 ml, and 16 drops (1ml/72drops)= 0.22 ml. [We need these volumes to determine the mass of stearic acid from mass concentration given.]
Unknown informations are:
V (volume in ml) =?
The mole of stearic acid used =?
Strategy
To calculate the mole of stearic acid used, we need the mass of stearic acid from the mass concentration. To get this we need a volume. Notice that those volumes (drops) are not the same ( it is safe to say that there is an error in the readings, as they were done independently). Therefore, we would find two or three values whose difference is smaller ( there is a little error). Subtract the smaller number from the larger number till you get a smaller difference ( do this for all three values).
The set of numbers with the smallest difference is 0.29 - 0.28=0.014, our concordant value.
Solutions
Now we us this set of numbers, 0.29-0.28, to determine an average volume :
V = (0.29-0.28)/2 (ml)
V= 0.285 ml
Now we can calculate the mass of stearic acid from the mass concentration:
m = C*V; m is the mass, C is the concentration in g/ ml, and V is the volume in ml.
m = (1.64*10^-4 g/ml)*(0.285 ml)
m = 4.674*10^-5 g
The mole of stearic acid used:
n = m/MM l; n is the mole of stearic acid, m is the mass of stearic acid, and MM is the molar mass of stearic acid.
n = 4.674*10^-5 g (284 g/mol)
n = 1.3274*10^-3
How many molecules of stearic acid would there be if it was 1 mol of stearic acid?
1 mol = 6.02214*10^23 molecule
Therefore, a conversion fraction would be:
6.02214*10^23 molecule/ 1 mol
Solution
Molecules of stearic acid in 1 mol =
1.3274*10^-3 mol (6.02214*10^23 molecule/ 1 mol)
= 7.994*10^20 molecules in 1 mol of C18H16O2
Name the following base: Ba(OH)2
Answer:
Caustic Base
Explanation:
"Barium hydroxide forms a strong caustic base in aqueous solution. It has many uses, e.g., as a test for sulphides; in pesticides; in the manufacture of alkali and glass. Use of barium hydroxide lime rather than soda lime, high sevoflurane concentration, high absorbent temperature, and fresh absorbent use."
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what is the mass of 0.083 moles of iron to the nearest tenth
Answer:
The answer is 0.01790670606142. We assume you are converting between moles Iron and gram.
Explanation:
The mass of 0.083 moles of iron to the nearest tenth is 0.4635135 grams.
What is mass?Mass is defined as the amount of substance contained in a particle or object as a dimensionless quantity. An object's mass is the entire amount of matter it contains. A scalar quantity, it. By using beam balance, it is measured. The object's mass is constant everywhere it is. The inertia of an object allows us to calculate its mass.
One carbon-12 atom weighs exactly 12 atomic mass units, which equals its atomic mass. One mole of carbon-12 atoms weighs exactly 12 grams; this is known as the molecular mass of carbon-12.
Molar mass of iron is 55.847 moles
Molar mass = mass/mole
Mass = molar mass x mole
Mass = 55.845 x 0.083
Mass = 0.4635135 grams.
Thus, the mass of 0.083 moles of iron to the nearest tenth is 0.4635135 grams.
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11. A mixture of magnesium powder and lead (II) Oxide will react vigorously when heated
but no reaction occurs when a mixture of magnesium oxide and lead powder are heated,
a) Explain the observation.
b Which of the two substances, magnesium or lead(IT) Oxide is;
i) Oxidized in the reaction?
ii) Oxidizing agent?
C Which is the most reactive metal
Please help
Answer:
Explanation:
The reaction is violent but safe, provided the procedure is followed exactly. ... Chemicals. Magnesium powder (HIGHLY FLAMMABLE), 0.25 g (note 4); Copper(II) oxide powder ... top must NOT be hot when the magnesium powder/copper oxide mix is added. ... After one or two minutes (be patient) a vigorous reaction occurs.
How many moles of Fe are needed to react with 0.95 moles of 02? Show work
Answer:
4
Explanation:
1N2 + 3H2 2NH3
Which of the following are also compounds? Select all that apply.
A.
CuFeS2
B.
H2O
C.
KCl
D.
Mg
E.
Cl
Answer:
option B,C and A are compound
What is the charge of a Li ion?
A. +1
B. +2
C. -1
D.-2
Answer:
A
Explanation:
because the charge of Li ion is +1 well I don't know the explanation yet but I'm sure about the answer
HI dissociates to form 12 and Hz: 2HI(g) → H2(g) + 12(9) If the concentration of Hl changes at a
rate of -0.45 mol L's? what is the rate of appearance of 12(g)?
Based on the rate of disappearance of HI, the rate of appearance of I₂ is 0.225 mol/L/s.
What is rate of reaction?
The rate of a reaction is the rate at which reactant molecules are converted to product or the rate at which product molecules are formed.
Rate of reaction = change in concentration of reactant or product/timeFrom the equation of the reaction, 2 moles of HI produces 1 mole of I₂.
The rate of disappearance of HI is -0.45 mol/L/s
The rate of appearance of I₂ will be 0.45/2 mol/L/s = 0.225 mol/L/s.
Therefore, the rate of appearance of I₂ is 0.225 mol/L/s.
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Number 12 (c) and (d) please help
Answer:
check below
Explanation:
c) Concentrated sulphuric acid is used a drying agent.
d) (use any one of them) Concentrated phosphoric acid, hot aluminium oxide, calcium chloride , anhydrous calcium sulphate
Answer:
12c) it is used as a drying agent
d) anhydrous calcium chloride
calcium oxide can also be used as a drying agent
10 How does no-till farming help the environment?
A It decreases soil erosion.
C It increases fertilizer use.
B It increases soil removal.
D It decreases crop yield.
Answer: Answer is A it will decrease soil erosion
Explanation:it just will trust me
Answer:
A.
Explanation:
the soil will not loosen when u till it
A parachute slows a skydiver from 85 m/s
to 45 m/s in 4.5 seconds? What is the
acceleration of the parachute?
A. 8.9 m/s2
B. -8.9 m/s
2
C. 0.1 m/s2
D. -0.1 m/s
2
Answer:
[tex]\boxed {\boxed {\sf B. \ -8.9 \ m/s^2}}[/tex]
Explanation:
Acceleration is found by dividing the change in velocity by the change in time.
[tex]a=\frac {v_f-v_i}{t}[/tex]
The parachute slows from 85 m/s to 45 m/s. Therefore, the final velocity is 45 meters per second and the initial velocity is 85 meters per second. The time is 4.5 seconds.
[tex]v_f= 45 \ m/s \\v_i= 85 \ m/s \\t= 4.5 \ s[/tex]
Substitute the values into the formula.
[tex]a= \frac {45 \ m/s- 85 \ m/s}{4.5 \ s}[/tex]
Solve the numerator and subtract.
[tex]a= \frac {-40 \ m/s}{4.5 \ s}[/tex]
Divide.
[tex]a=-8.888888889 \ m/s/s[/tex]
If we round this to the nearest tenth, the 8 in the hundredth place tells us to round the 8 up to a 9.
[tex]a \approx -8.9 \ m/s/s= -8.9 \ m/s^2[/tex]
The acceleration of the parachute is approximately -8.9 meters per square second. The value is negative because the parachute is slowing down.
7. Cells often store materials like water, salts, proteins and carbohydrates in sac-like structures called A. Chloroplasts. B. Lysosomes. C. Mitochondria. D. Vacuoles.
Answer:
A
Explanation:
the chloroplast holds the water , nutrients
Answer:
[tex]\boxed {\boxed {\sf D. \ Vacuoles}}[/tex]
Explanation:
First, let's examine each answer choice.
A. Chloroplasts
These structures are only found in plant cells. They are the site of photosynthesis: the process that turns water, carbon dioxide, and light energy into glucose and oxygen.B. Lysosomes
These help remove and break down cellular waste. They contain special enzymes that allow them to digest certain molecules, bacteria, and old parts of the cell.C. Mitochondria
These are famously known as the powerhouse of the cell. They create energy from glucose and oxygen in a process called cellular respiration.D. Vacuoles
Vacuoles are sacs that store substances, including water, nutrients, and waste.Since the question asks us to pick the sac-like structures that store materials in cells, choice D: vacuoles is correct.
plss help me in this question
Answer:
[tex]m_{CO_2}=0.88g[/tex]
Explanation:
Hello there!
In this case, since we are talking about a decomposition reaction whereby calcium carbonate is decomposed to calcium oxide and carbon dioxide according to the following chemical equation:
[tex]CaCO_3\rightarrow CaO+CO_2[/tex]
Next, we must recall the law of conservation of mass which states that matter cannot be neither created nor destroyed so the mass of calcium carbonate equal the addition of the mass of both calcium oxide and carbon dioxide:
[tex]m_{CaCO_3}=m_{CaO}+m_{CO_2}[/tex]
Which must be solved for the mass of carbon dioxide as we are given those of calcium carbonate and calcium oxide:
[tex]m_{CO_2}=m_{CaCO_3}-m_{CaO}\\\\m_{CO_2}=2.00g-1.12g\\\\m_{CO_2}=0.88g[/tex]
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How many liters of ammonia gas can be formed from 24.5 L of hydrogen gas at STP?
Answer: 16.3 L of ammonia gas can be formed from 24.5 L of hydrogen gas at STP
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
The balanced chemical equation is:
[tex]3H_2+N_2\rightarrow 2NH_3[/tex]
According to stoichiometry :
[tex]3\times 22.4=67.2L[/tex] of [tex]H_2[/tex] produce = [tex]2\times 22.4=44.8L[/tex] of [tex]NH_3[/tex] at STP
Thus 24.5 L of [tex]H_2[/tex] will produce= [tex]\frac{44.8}{67.2}\times 24.5=16.3L[/tex] of [tex]NH_3[/tex] at STP
Thus 16.3 L of ammonia gas can be formed from 24.5 L of hydrogen gas at STP
4.550 g of Na2SO4 are added to 0.350 L of water. To this solution, 0.085 L of water were added. What is the new concentration of the solution?
Answer:
0.0736 M or 10.4 g/L
Explanation:
First we convert 4.550 g of Na₂SO₄ into moles, using the molar mass of Na₂SO₄:
4.550 g ÷ 142.04 g/mol = 0.0320 molThen we calculate the final volume of the solution:
Final Volume = 0.350 L + 0.085 LFinal Volume = 0.435 LNow we can proceed to calculate the concentration -in molarity- of the solution:
Molarity = moles / liters0.0320 mol / 0.435 L = 0.0736 MIn g/L the concentration would be:
4.550 g / 0.435 L = 10.4 g/LWhat are the three ways there can be a base change in a sequence?
Answer:
substitutions, deletions and insertions
The volume of a gas is 550 mL at 960 mm Hg and 200.0 C. What volume
would the pressure of the gas be 830 mm Hg if the temperature is reduced
to 150.0C? Make sure your answer is rounded to nearest whole number
and your final answer has the units of mL. *
Answer:
The volume will be 568.89 mL.
Explanation:
Boyle's law says that "The volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure"
Boyle's law is expressed mathematically as:
Pressure * Volume = constant
or P * V = k
Gay-Lussac's law indicates that when there is a constant volume, as the temperature increases, the pressure of the gas increases. And when the temperature is decreased, the pressure of the gas decreases. That is, the pressure of the gas is directly proportional to its temperature. Gay-Lussac's law can be expressed mathematically as follows:
[tex]\frac{P}{T}=k[/tex]
Where P = pressure, T = temperature, K = Constant
Finally, Charles's law indicates that as the temperature increases, the volume of the gas increases and as the temperature decreases, the volume of the gas decreases. In summary, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:
[tex]\frac{V}{T}=k[/tex]
Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:
[tex]\frac{P*V}{T} =k[/tex]
Studying an initial state 1 and a final state 2, it is fulfilled:
[tex]\frac{P1*V1}{T1} =\frac{P2*V2}{T2}[/tex]
In this case:
P1= 960 mmHgV1= 550 mLT1= 200 C= 473 K (being 0 C=273 K)P2= 830 mmHgV2= ?T2= 150 C= 423 KReplacing:
[tex]\frac{960 mmHg*550 mL}{473K} =\frac{830 mmHg*V2}{423 K}[/tex]
Solving:
[tex]V2=\frac{423 K}{830 mmHg} *\frac{960 mmHg*550 mL}{473K}[/tex]
V2= 568.9 mL
The volume will be 568.89 mL.
WILL MARK BRAINLEST
Which of the following are sources of greenhouse gasses? Select all that apply
a
Bike Riding
b
Cow Farts
c
Growing Trees
d
Burning Coal
e
Car Exhaust
Answer:
b and c
Explanation:
sorry if i'm wrong
Answer:
b, c, d, e
Explanation:
If 50 milliliters of 0.50 M HCl is used to completely neutralize 25 milliliters of KOH solution, what is the molarity of the base?
Answer:
0.25 M
Explanation:
4. How many molecules are equal to 2.25 moles of sulfur dioxide?
5. How many moles are equal to 2.4 x 1023 particles of sodium chloride?
Answer: 4. We know that one mole of any chemical compound always contains 6.022 x 10^23 molecules. Therefore, we can calculate the number of molecules of 2.25 moles of sulfur dioxide SO2 by multiplying the number of moles by the Avogadro's constant 6.022 x 10^23:
2.25 moles SO2 (6.022x10^23 molecules/1mole) = 1.355 x 10^24 molecules of sulfur dioxide
5. The number of moles of sodium chloride are 0.40 moles
Explanation:
What volume, in liters, does the following quantity of gas at STP occupy?
7.8*10^15
thank you
Answer:
2.9x10⁻⁷L is the volume this amount of gas occupy
Explanation:
Assuming there are 7.8x10¹⁵ atoms
Based on the general gas law:
PV = nRT
Where P is pressure = 1atm
V is volume = Our incognite
n are moles of the gas:
7.8x10¹⁵ atoms * (1mol / 6.022x10²³ atoms) = 1.30x10⁻⁸ moles of gas
R is gas constant = 0.082atmL/molK
And T is absolute temperature = 273.15K at STP
Solving for Volume:
V = nRT/P
V = 1.30x10⁻⁸ moles*0.082atmL/molK*273.15K / 1atm
V = 2.9x10⁻⁷L is the volume this amount of gas occupy
why does the sky appear orang or red at sunset and sunrise?
Answer:
Because the sun is low on the horizon, sunlight passes through more air at sunset and sunrise than during the day, when the sun is higher in the sky. More atmosphere means more molecules to scatter the violet and blue light away from your eyes.
Explain what helps convert non-rich oxygen blood cells back to oxygen rich cells?
Answer:
As blood travels through the body, oxygen is used up, and the blood becomes oxygen poor. Oxygen-poor blood returns from the body to the heart through the superior vena cava (SVC) and inferior vena cava (IVC), the two main veins that bring blood back to the heart.
Explanation:
The blades of a wind turbine are at rest until the movement of air causes the blades to spin.
Which energy transformation happens when the blades are spinning as shown?
Answer:
C
Explanation:
First there is no chemicals involved so cross out B and D. Wind turbines are made to create energy not to convert it so A is crossed out as well. The remaining answer is C.
The energy is transformed from mechanical to electrical when the blades are spinning, as shown.
What are wind turbines?
Wind turbines are large fans that convert the kinetic energy of wind into electrical energy.
The blades run by winds and generate electricity.
They are helpful, but they are a threat to birds and bats.
Thus, the correct option is C, mechanical to electrical energy.
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Which of these is a learned behavior of a dog?
1.Begging for food
2.Drinking water
3.Panting on a hot day
4.Chewing on a bone
Which type of ion usually undergoes reduction?
No ion
All ions
Anion
Cation
Answer:
anion
Explanation:
anion undergoes reduction.
cation undergoes oxidation.
The ions are categorized according to the process of oxidation and reduction. The ion usually undergoes reduction is an anion.
What is reduction?A process involving the partial or complete gain of electrons and loss of oxygen. The ions acquire a net negative charge on them.
Thus, anions usually undergo a reduction.
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Please help me ........
How did the us stop the spread of communism during the Cold War
Answer:
With the policies of containment, the United States hoped to effectively stop the spread of communism and their newest threat. After the war, the United States and the Soviet Union had very different ideas on how to rebuild.
The hammerhead shark can reproduce both sexually and asexually. What characteristic of the offspring would suggest that they were produced
through sexual reproduction? Offspring are-
all the same gender.
genetically diverse.
produced in small number.
produced very slowly.
Answer: I think it is ‘Genetically diverse’
Explanation:
What is the pH of 4.3x10^-7 M solution of H2CO3?
A.)7
B.)4.3
C.)6.4
D.)7.6
ASAP PLS
Answer:
pH = -log[H⁺] = -log(4.75 x 10⁻⁷) = -(- 6.32 ) = 6.32
Explanation:
Given 4.3 x 10⁻⁷M H₂CO₃ (Ka1 = 4.2 x 10⁻⁷ & Ka2 = 4.8 x 10⁻¹¹)
Note: The Ka2 value for the 2nd ionization step is so small (Ka2 = 4.8 x 10⁻¹¹) It will be assumed all of the hydronium ions (H⁺) come from the 1st ionization step.
1st Ionization step
H₂CO₃ ⇄ H⁺ + HCO₃⁻
C(initial) 4.3 x 10⁻⁷ 0 0
ΔC -x +x +x
C(final) 4.3 x 10⁻⁷ - x x x
Note: the 'x' value in this analysis can not be dropped as the Conc/Ka value is less than 10². In this case he C/Ka ratio* (4.3E-7/4.2E-7 ≈ 1) is far below 10².
So, one sets up the equilibrium equation to be quadric and the x-value can be determined.
Ka1 = [H⁺][HSO⁻]/[H₂SO₃] = (x)(x)/(4.3 x 10⁻ - x) = x²/(4.3 x 10⁻⁷ - x) = 4.2 x 10⁻⁷
=> x² = 4.2 x 10⁻⁷(4.3 x 10⁻⁷ - x)
=> x² + 4.2 x 10⁻⁷x - 1.8 x 10⁻¹³ = 0
a = 1, b = 4.2 x 10⁻⁷, c = - 1.8 x 10⁻¹³
x = b² ± SqrRt(b² - 4(1)(-1.8 x 10⁻¹³ / 2(1) = 4.75 x 10⁻⁷
x = [H⁺] = 4.75 x 10⁻⁷
pH = -log[H⁺] = -log(4.75 x 10⁻⁷) = -(- 6.4 ) = 6.4
______________________
* The Concentration/Ka-value is the simplification test for quadratic equations used in Equilibrium studies. If the C/Ka > 100 then one can simplify the C(final) by dropping the 'x' if used in this type analysis. However, if the C/Ka value is < 100 then the x-value must be retained and the solution is determined using the quadratic equation formula.
for ax² + bx + c = 0
x = b² ± SqrRt(b² - 4ac) / 2a
Earth's polar regions have cold, dry climates because the sun's rays are at a ?
Answer:
not reaching to the polesExplanation:
Answer:
the rays strike at a low level in the polar region
Explanation:
okay so since the polar zones lie between 66.50 north or south the polar regions are always so cold is because strike the low parts
hope this helped!
