Calculate the number of moles in 15 liters of oxygen at STP.
O 0.67 mol
O 67 mol
O 360 mol
O 1.5 mol
Answer:
.67 mole
Explanation:
Using ideal gas law
PV = n RT
P = pressure = 1 atm at STP
T = 273.15 K at STP
V = 15 L
R = .082057 L-atm / K-mol
Subbing in those values:
1 (15) = n (.082057) (273.15 ) results in n = .669 moles
Which of the following is NOT an example of a colligative property?
Group of answer choices
A. Salt is added to ice to make homemade ice cream.
B. Salt is added to roads before a snow storm.
C.Antifreeze is added to a radiator of a car.
D. Salt water dehydrates someone that drinks it.
Salt-water that dehydrates someone who drinks is NOT an example of a colligative property (Option D).
What are Colligative Properties?Colligative Properties make reference to physical properties associated with solute concentration instead of its intrinsical characteristics.
Some examples of colligative properties include boiling state, vapour pressure, and osmotic pressure due to the presence of ionic particles.
In conclusion, salt-water that dehydrates someone who drinks is NOT an example of a colligative property (Option D).
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1. Consider the unbalanced equation:
Al4C3 (s) + H2O (l) ---> Al(OH)3 (s) + CH4 (g)
How many moles of H2O are needed to react with 1.48 moles of Al4C3 ?
Hint: Write the balanced equation first
2.
Consider the balanced equation:
2 CH4 (g) + 3 O2 (g) + 2 NH3 ---> 2 HCN (g) + 6 H2O (g)
If 203.6 g of NH3 is reacted with excess CH4 and O2, what mass in grams of HCN is produced?
Answer:
1.) 17.76 moles H₂O
2.) 323.1 g HCN
Explanation:
1.) An equation is balanced when there is an equal amount of each element on both sides of the reaction. The quantities can be modified by adding coefficients in front of the molecules.
The unbalanced equation:
Al₄C₃(s) + H₂O -----> Al(OH)₃(s) + CH₄(g)
Reactants: 4 aluminum, 3 carbon, 2 hydrogen, 1 oxygen
Products: 1 aluminum, 1 carbon, 7 hydrogen, 3 oxygen
The balanced equation:
Al₄C₃(s) + 12 H₂O -----> 4 Al(OH)₃(s) + 3 CH₄(g)
Reactants: 4 aluminum, 3 carbon, 24 hydrogen, 12 oxygen
Products: 4 aluminum, 3 carbon, 24 hydrogen, 12 oxygen
Now that the equation is balanced, you can use the relevant coefficients to construct a mole-to-mole ratio. This will allow you to convert between moles Al₄C₃ to moles H₂O.
1.48 moles Al₄C₃ 12 moles H₂O
---------------------------- x ------------------------ = 17.76 moles H₂O
1 mole Al₄C₃
2.) To find the mass of HCN, you need to (1) convert grams NH₃ to moles NH₃ (via molar mass), then (2) convert moles NH₃ to moles HCN (via mole-to-mole from equation coefficients), and then (3) convert moles HCN to grams HCN (via molar mass). It is important to arrange the coefficients in a way that allows for the cancellation of units.
Molar Mass (NH₃): 14.009 g/mol + 3(1.008 g/mol)
Molar Mass (NH₃): 17.033 g/mol
Molar Mass (HCN): 1.008 g/mol + 12.011 g/mol + 14.009 g/mol
Molar Mass (HCN): 27.028 g/mol
2 CH₄(g) + 3 O₂(g) + 2 NH₃(g) ------> 2 HCN(g) + 6 H₂O(g)
203.6 g NH₃ 1 mole 2 moles HCN 27.028 g
--------------------- x ---------------- x ------------------------ x ----------------- =
17.033 g 2 moles NH₃ 1 mole
= 323.1 g HCN
Which of these is an example of a physical property? A. Iron rusts when exposed to air. B. Table salt is a white crystal. C. Sodium oxidizes in air. D. Potassium ignites when placed in water.
Explanation:
Iron rusts when exposed to air,Sodium oxidizes in air,Potassium ignites when placed in water.These all are irreversible reaction .What is physical change ? When a substance change its physical state No new chemical is formedExamples :- Boling of water, melting of solids, shredding of paper.What volume of a 0.550 M solution of potassium hydroxide (KOH) can be made with 19.9 g of potassium hydroxide?
Answer:
0.645 L
Explanation:
To find the volume, you need to (1) convert grams to moles (using the molar mass) and then (2) calculate the volume (using the molarity ratio). The final answer should have 3 sig figs to match the sig figs of the given values.
(Step 1)
Molar Mass (KOH): 39.098 g/mol + 15.998 g/mol + 1.008 g/mol
Molar Mass (KOH): 56.104 g/mol
19.9 grams KOH 1 mole
-------------------------- x ----------------------- = 0.355 moles KOH
56.014 grams
(Step 2)
Molarity = moles / volume <----- Molarity ratio
0.550 M = 0.355 moles / volume <----- Insert values
(0.550 M) x volume = 0.355 moles <----- Multiply both sides by volume
volume = 0.645 L <----- Divide both sides by 0.550
If 1.240g of carbon dioxide dissolves in 1.01L of water at 755mmHg, what quantity of carbon dioxide in grams will dissolve at 790mmHg?
Taking into account the Henry's Law, 1.297 g carbon dioxide will dissolve at 790 mm Hg in 1.01 L water.
Henry's LawA change in pressure does not appreciably influence the solubility of solids or liquids or liquids in liquids; however, that of gases in solvents increases when the partial pressure of the gases increases. The solubility of a gas depends on pressure and temperature.
In this way, Henry's Law describes the effect of pressure on the solubility of gases. This law states that the solubility of a gas in contact with the surface of a liquid at a given temperature is directly proportional to the partial pressure of said gas on the liquid.
Mathematically, Henry's law is expressed as:
C=k×P
Where:
P is the partial pressure of the gas.C is the concentration of the gas.k is Henry's constant, which depends on the nature of the gas, the temperature, and the liquid.At 2 different partial pressure values, the Henry's law is expressed as:
[tex]\frac{C1}{C2} =\frac{P1}{P2}[/tex]
Quantity of carbon dioxideIn this case, you know:
C₁ = [tex]\frac{1.240 g}{1.01 L}[/tex] =1.228 [tex]\frac{g}{L}[/tex]C₂ = ?P₁ = 755 mm HgP₂ = 790 mm HgReplacing in Henry's Law:
[tex]\frac{1.228\frac{g}{L} }{C2} =\frac{755 mmHg}{790mmHg}[/tex]
Solving:
[tex]1.228\frac{g}{L} =\frac{755 mmHg}{790mmHg}xC2[/tex]
C2= [tex]\frac{1.228\frac{g}{L} }{\frac{755 mmHg}{790mmHg}}[/tex]
C2= 1.285 [tex]\frac{g}{L}[/tex]
Then, the concentration of carbon dioxide at 790 mmHg is 1.285 g/L. But you have 1.01 L of water. So the amount of gas dissolved can be calculated as 1.01 L×1.285 g/L = 1.297 g
Finally, 1.297 g carbon dioxide will dissolve at 790 mm Hg in 1.01 L water.
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What is an alkaline
Answer:
is a solution whose pH is above 7or is a basic solution
What mass (g) of calcium chloride, CaCl2, is needed to prepare 2.451 L of a 1.56 M solution
Answer:
424 grams CaCl₂
Explanation:
To find the mass of CaCl₂, you need to (1) calculate the moles (using the molarity ratio) and then (2) convert moles to grams (using the molar mass). The final answer should have 3 sig figs to match the given value with the least amount of sig figs.
(Step 1)
Molarity (M) = moles / volume (L)
1.56 M = moles / 2.451 L
3.82 = moles
(Step 2)
Molar Mass (CaCl₂): 40.078 g/mol + 2(35.453 g/mol)
Molar Mass (CaCl₂): 110.984 g/mol
3.82 moles CaCl₂ 110.984 g
---------------------------- x ------------------- = 424 grams CaCl₂
1 mole
What is the
molality of 30g of NACI dissolved in 350g of water
Answer:
1.45 mol/kg
Explanation:
nilered videos
Answer:
1.47 m
Explanation:
The molality can be found using the following equation:
Molality = moles solute / mass (kg) solvent
In this case, NaCl is the solute and H₂O is the solvent. To find the molality, you need to (1) convert grams NaCl to moles (via the molar mass), then (2) convert grams H₂O to kilograms, and then (3) calculate the molality.
(Step 1)
Molar Mass (NaCl): 22.990 g/mol + 35.453 g/mol
Molar Mass (NaCl): 58.443 g/mol
30 grams NaCl 1 mole
-------------------------- x ------------------------ = 0.513 moles NaCl
58.443 grams
(Step 2)
1,000 grams = 1 kg
350 grams H₂O 1 kg
-------------------------- x ----------------------- = 0.35 kg H₂O
1,000 grams
(Step 3)
Molality = moles solute / mass (kg) solvent
Molality = 0.513 moles NaCl / 0.35 kg H₂O
Molality = 1.47 m
What is the chemical symbol of the terminal atom in the lewis structure of OH- ?
Answer:
kindly refer to the picture attached
Explanation:
Have a great day . keep smiling
Find the amount of heat energy needed to convert 150 grams of ice at -15°C to ice at -63°C.
Group of answer choices
A. (-) 14760 Joules because the ice is being heated.
B. (-) 14760 Joules because the ice is cooling.
C. 14760 Joules because the ice is cooling.
D. 14760 Joules because the ice is being heated.
The heat needed is (-) 14760 Joules because the ice is cooling.
What is heat?The term heat refers to a form of energy that can be observed as a result of temperature difference between two bodies. We can recall that heat always flows from the hotter to the cooler body.
Given that the heat added to a substance can be calculated by the use of H = mcdT
Where;
H = heat
m = mass
c = specific heat capacity
T = temperature change
Hence;
H = 150 g * 2.03 Jg∘C * (-63 - (-15))
H = (-) 14760 J
Hence the heat needed is (-) 14760 Joules because the ice is cooling.
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Write the chemical equation for the autoionization of water and label the conjugate
acid-base pairs.
The equation for the autoionization of water is-
NH3 + H2O → NH4+ + OH− (H2O acts as an acid)
HCl + H2O → H3O+ + Cl− (H2O acts as a base)
What do you mean by the autoionization of water ?Autoionization of water, the autoionization constant Kw, and the relationship between [H⁺] and [OH⁻] in aqueous solutions.
Water can undergo autoionization to form and ions.
The expression for the autoionization constant is
[tex]The expression for the autoionization constant isK_\text{w}=[\text{H}_3\text{O}^+][\text{OH}^-]\quad\quad\text{(Eq. 1)}K w =[H 3 O + ][OH − ][/tex]
In this way the autoionization of water,
NH3 + H2O → NH4+ + OH− (H2O acts as an acid)
HCl + H2O → H3O+ + Cl− (H2O acts as a base) is given.
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How many moles of solute particles are present in 1 mL (exact) of aqueous 0.0040 M Ba(OH)2?
The number of mole of solute particles are present in 1 mL (exact) of aqueous 0.0040 M Ba(OH)₂ is 0.000004 mole
What is molarity?Molarity is defined as the mole of solute per unit litre of solution. Mathematically, it can be expressed as:
Molarity = mole / Volume
With the above formula, we can determine the number of mole present in the solution. Detail below:
How to determine the mole of the solute in the solutionVolume of solution = 1 mL = 1 / 1000 = 0.001 LMolarity of solution = 0.004 MMole of solute =?Molarity = mole / Volume
Cross multiply
Mole = Molarity × volume
Mole of solute = 0.004 × 0.001
Mole of solute = 0.000004 mole
Thus, the mole of the solute in the solution is 0.000004 mole
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Consider the following reaction at 298K.
Pb2+ (aq) + Cu (s) Pb (s) + Cu2+ (aq)
Which of the following statements are correct?
Choose all that apply.
The reaction is product-favored.
delta G^o < 0
n = 4 mol electrons
K < 1
Eo cell < 0
The true statements are;
K < 0Eocel < 0What is a redox reaction?We define a redox reaction as one in which a specie is oxidized and another is reduced.
Now;
Eo cell = cell potential = -0.13 V - (+0.34 V) = -0.47 V
n =number of moles of electrons = 2 mole of electrons
K = equilibrium constant
ΔG = change in free energy
Eo cell = 0.0592/n log K
-0.47 = 0.0592/2 log K
log K = -0.47 * 2/0.0592
K = 1.3 * 10^-16
ΔG = -nFEo cell
ΔG = -(2 * 96500 * -0.47)
ΔG = 90.7kJ
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Why does direct titration of aspirin with NaOH have a side reaction and how to prevent it?
Direct titration of aspirin with NaOH have a side reaction simply because aspirin is a weak acid
What is direct titration?
Direct titration can simply be defined as a type of titration in which a titrant of known concentration and volume is added to a substance in order to analyze it.
As the name implies, it is called direct titration simply because the one approaches the endpoint of the experiment directly.
Furthermore, the significance of direct titration is that it is used to find the quantity of a substance within a solution with chemical reactions.
So therefore, direct titration of aspirin with NaOH have a side reaction simply because aspirin is a weak acid
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The value of the entropy change for the process N₂ (g) + 3H₂ (g) --> 2NH₃ (g) is ________.
positive
unchanged
zero
negative
Answer:
negative
Explanation:
Entropy is a measure of the "disorder" in a system.
In this reaction, the amount of disorder decreases. This is because one gas molecule (NH₃) has more order than two gas molecules (N₂ and H₂). Therefore, the entropy change should be negative.
What does quantization refer to?
OA. Being able to move around freely
OB. Involving uncertainty in knowing a value
OC. Having a specific set of possible values
OD. Occupying a place in a continuous range
Answer:
Having a specific set of possible values
what does it mean Emphasis on object vs woman
Emphasis on object vs woman simply means s- e- x- ual objectification
This goes to say that it emphasizes seeing women as objects of se- xu- al pleasure
What is objectification?Objectification simply refers to the act of treating or viewing a person as an object, devoid of thought or feeling.
Most of the time, objectification is targeted at women and reduces them to objects of se- xu- al pleasure
So therefore, emphasis on object vs woman simply means se- xu- al objectification
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Heating up a reaction does which of the following:
Group of answer choices
A. Increases the number of collisions as well as the strength of the collision
B. Increases the strength of the collisions only.
C. Increases the number of collisions only.
D. No effect is found on the reaction by increasing the temperature.
Heating up a reaction does increase the number of collision only.
Hence, Option C is correct answer.
What is Collision Theory ?According to the collision theory, the reaction take place when the collision occur and molecules having sufficient energy or threshold energy for collision.
The collision of molecules depend on the kinetic energy of molecules. Greater the kinetic energy greater the number of molecules collide. Lesser the kinetic energy lesser will be collision.
How temperature affect the collision theory ?With an increase in temperature, there is an increase in energy that can be converted into activation energy in a collision, and that will increase the reaction rate. A decrease in temperature would have the opposite effect. With an increase in temperature, there is an increase in the number of collision.
Thus from the above conclusion we can say that Heating up a reaction does increase the number of collision only.
Hence, Option C is correct answer.
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write three disadvantages of hard water.
The three disadvantages of hard water are:
1. Hard water is unsuitable for washing because soap does not readily create a lather in it.
2. Soap may react and produce, wasting the soap.
3. Due to the development of calcium and magnesium carbonates, tea kettles will get furred.
Hard waterWater that contains a lot of minerals is referred to as hard water. In limestone, chalk, or gypsum deposits, which are mostly composed of calcium and magnesium carbonates, bicarbonates, and sulphates, hard water is created as a result of percolation. A moderate health advantage from drinking hard water is possible. In industrial settings where water hardness is regulated to prevent expensive breakdowns in boilers, cooling towers, and other water-handling equipment, it can present serious issues. Hard water is frequently detected in home settings by the build-up of lime scale in kettles and water heaters as well as by the absence of foam when soap is agitated in water. Wherever there is a worry about water hardness, water softening is frequently employed to lessen the negative impacts of hard water.
write three disadvantages of hard water.
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The isotope sodium-24 has a half-life of 15 hours. Starting with 22 grams, how much remains in 30
hours?
Answer:
5.5 grams
Explanation:
To find how much of the isotope remains, you need to use the half-life equation:
[tex]N(t) = N_0(\frac{1}{2})^\frac{t}{h}[/tex]
In this equation,
-----> N(t) = remaining mass (g)
-----> N₀ = initial mass (g)
-----> t = time (hrs)
-----> h = half-life (hrs)
You can find the remaining mass by plugging the given values into the equation and solving.
N(t) = ? g t = 30 hrs
N₀ = 22 g h = 15 hrs
[tex]N(t) = N_0(\frac{1}{2})^\frac{t}{h}[/tex] <----- Half-life equation
[tex]N(30) = (22)(\frac{1}{2})^\frac{30}{15}[/tex] <----- Insert values
[tex]N(30) = (22)(\frac{1}{2})^2[/tex] <----- Simplify exponent
[tex]N(30) = (22)(0.25)[/tex] <----- Solve [tex](\frac{1}{2} )^2[/tex]
[tex]N(30) = 5.5[/tex] <----- Multiply 22 and 0.25
A piece of copper absorbs 5000 J of energy and undergoes a temperature change from 100 °C to 200 °C. What is the mass of the piece of copper?
Group of answer choices
A. 12.9 grams
B. 129.9 grams
C. 0.385 grams
D. 1290 grams
Answer:
B.) 129.9 grams
Explanation:
To find the mass, you need to use the following equation:
Q = mcΔT
In this equation,
-----> Q = energy (J)
-----> m = mass (g)
-----> c = specific heat (J/g°C)
-----> ΔT = change in temperature (°C)
The specific heat of copper is 0.385 J/g°C. Knowing this, you can plug the given values into the equation and simplify to isolate "m".
Q = mcΔT <----- Equation
5000 J = m(0.385 J/g°C)(200 °C - 100 °C) <----- Insert values
5000 J = m(0.385 J/g°C)(100) <----- Subtract
5000 J = m(38.5) <----- Multiply 0.385 and 100
129.9 = m <----- Divide both sides by 38.5
silver
nitrate
solution
A current was passed through the circuit shown in figure above. In the
experiment, 5.4 g of silver metal was discharged at the cathode in electrolysis cell
B. What mass of copper was discharged at the cathode in cell A?
[Molar mass: Ag = 108 gmol¹; Cu= 63.5 gmol ¹]
Answer:
Silver
Explanation:
What mass of copper was discharge at the cathode in a cell
Determine the acid dissociation constant (Ka) for a 0.200 M solution of hydrogen sulfate ion with
the pH of 1.35 if the reaction for the dissociation of this acid is
HSO 4 →→ H+ + SO 4-²
(Hint: [H+] = 10-PH; Ka = [product]/[reactant])
The acid dissociation constant(Ka) is 0.0095
The reaction for this dissociation of acid is
HSO4 ⇄H+ + SO4 -2
The dissociation constant can be determined from the following expression
[tex]Ka= \frac{[H+] [SO4]-2}{[HSO4}[/tex]
[H+] = 10-PH
= 10-1.35
[H+] = 0.0447
[H+] = 0.0447 mol / L
From equation, [H+] = [SO4-2] = 0.0447 mol / L
[SO4-2] = 0.0447 mol / L
From the values of [H+], [SO4-2] and [HSO4] Ka can be calculated as follows,
Ka = 0.0447 * 0.0447 / 0.200
= 0.0019 / 0.200
= 0.0095
Hence the value of the acid dissociation constant (Ka) for the given reaction is 0.0095
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Select the correct answer. A ball hits a wall. What is true about the magnitude of the force experienced by the ball compared with the force experienced by the wall? A. The ball experiences more force than the wall. B. The ball experiences less force than the wall. C. The ball and the wall experience the same force. D. The ball experiences half the force of the wall.
Answer:
C
Explanation:
For every action there is an equal but opposite reaction..... the forces are the same
Ideal Gas Law: Tutorial. At a party, you use a gas canister to fill balloons. The canister holds 4.47 moles of air. If the room is at 26.0°C and the gas pressure is 855 kilopascals, what is the volume of the canister? The volume of the canister is ___ liters. Type the correct answer in the box. Express your answer to the correct number of significant figures. Use the gas laws Fact sheet to help you.
Answer:
13.0 L
Explanation:
To find the volume, you need to use the Ideal Gas Law:
PV = nRT
In this equation,
-----> P = pressure (kPa)
-----> V = volume (L)
-----> n = moles
-----> R = Ideal Gas constant (8.314 kPa*L/mol*K)
-----> T = temperature (K)
After converting the temperature from Celsius to Kelvin, you can plug the given values into the equation and simplify to find "V". The final answer should have 3 sig figs to match the sig figs of the given values.
P = 855 kPa R = 8.314 kPa*L/mol*K
V = ? L T = 26.0 °C + 273.15 = 299.15 K
n = 4.47 moles
PV = nRT
(855 kPa)V = (4.47 moles)(8.314 kPa*L/mol*K)(299.15 K)
(855 kPa)V = 11117.48496
V = 13.0 L
Question 6(Multiple Choice Worth 5 points)
(08.01 LC)
Which of the following is a property of water?
It can freeze very fast.
OIt has low heat capacity.
It exists in all three states on Earth.
It repels other water molecules.
The property of water is that It exists in all three states on Earth.
The major residences to be able to be mentioned in this text are its appeal to polar molecules, its high specific warmth, the excessive warmness of vaporization, the decrease density of ice, and its high polarity.
The primary homes of water are its polarity, concord, adhesion, floor anxiety, excessive unique warmth, and evaporative cooling. A water molecule is barely charged on each ends. this is because oxygen is more electronegative than hydrogen.
Water is good sized functionality to dissolve a ramification of molecules has earned it the designation of “standard solvent,” and it's far this capacity that makes water such an invaluable life-sustaining pressure. On a biological level, water's role as a solvent facilitates cells transport and use substances like oxygen or vitamins.
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At the equivalence point of a titration of the [H+] concentration is equal to:
Group of answer choices
A. 1 x 107 M
B. 7
C. [OH-]
D. 1 x 10-7 M
B. At the equivalence point of a titration of the [H+] concentration is equal to 7.
What is equivalence point of a titration?The equivalence point of a titration is a point in titration at which the amount of titrant added is just enough to completely neutralize the analyte solution.
At the equivalence point in an acid-base titration, moles of base equals moles of acid and the solution only contains salt and water.
At the equivalence point, equal amounts of H+ and OH- ions combines as shown below;
H⁺ + OH⁻ → H₂O
The pH of resulting solution is 7.0 (neutral).
Thus, the pH at the equivalence point for this titration will always be 7.0.
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PLS
PLA HELP WOTH THIS CHEMISTRY WORK!!!
You have 250.0 mL of 4.00 M sugar solution. You add 332.4 mL of water to this solution.
Determine the concentration of the sugar solution after the water has been added
Answer:
1.72 M
Explanation:
To find the new molarity, you need to (1) convert both volumes from mL to L, then (2) calculate the moles (using the molarity equation), and then (3) calculate the new molarity (using the new volume and molarity equation). The final answer should have 3 sig figs.
(Step 1)
1,000 mL = 1 L
250.0 mL / 1,000 = 0.250 L
332.4 mL / 1,000 = 0.3324 L
(Step 2)
Molarity = moles / volume (L)
4.00 M = moles / 0.250 L
1.00 = moles
(Step 3)
New Volume = 0.3324 L + 0.250 L = 0.5824 L
Molarity = moles / volume
Molarity = 1.00 moles / 0.5824 L
Molarity = 1.72 M
