Answer:
72.4%
Explanation:
Step 1: Write the balanced equation
2 Cu + S ⇒ Cu₂S
Step 2: Calculate the theoretical yield, in moles, from 0.0970 moles of Cu
The molar ratio of Cu to Cu₂S is 2:1.
0.0970 mol Cu × 1 mol Cu₂S/2 mol Cu = 0.0485 mol Cu₂S
Step 3, Convert the theoretical yield to mass
The molar mass of Cu₂S is 159.16 g/mol.
0.0485 mol × 159.16 g/mol = 7.72 g
Step 4: Calculate the percent yield
We will use the following expression.
%yield = experimental yield/theoretical yield × 100%
%yield = 5.59 g/7.72 g × 100% = 72.4%
Select the correct answer.
For Al, its atomic number is 13 and its mass number is 27. How many neutrons does it have?
Ο Α. .
13
ОВ.
14
26
OD
27
O E
40
Answer:
B.) 14
Explanation:
27-13=14 neutrons
3. Calculate the number of nickel atoms in a 5-cent coin of mass 0.942g if it was made of an alloy consisting of 75% copper and 25% nickel
Answer:
2.41x10²¹ atoms
Explanation:
mass of nickel that are present in the coin can be determined Using ( 25% nickel) with j mass of coin= 0.942g )
mass of nickel = (0.942g) × (25/100)
= 0.2355g of Nickel
We need to convert this " gram" into " moles"
Mole= mass/ molar mass
Molar mass= 58.69 g/mol
0.2355 g) / (58.69 g/mol)
= 0.004 mol
We need to convert the moles to
number of atoms.
Avogadro's number= 6.023x10²³ atoms/mol
(0.004 × 6.023x10²³ atoms/mol)
=2.41x10²¹ atoms
What class of chemicals is responsible for ozone depletion?
Answer the following questions about the solubility of CoCO3(s). The value of Ksp for CoCO3(s) is 1.0 × 10^−10.
A. Calculate the value of [Co2+] in a saturated solution of CoCO3 in distilled water.
B. If 0.10 M of Co2+ is already present in distilled water, calculate the molar solubility of CoCO3(s).
C. Explain why CoCO3 is less soluble in distilled water that already contains Co2+
Answer:
Attached picture.
Explanation:
(1) Ksp equals the product of [Co 2+][CO3 2-]. CoCO3 is excluded from the equilibrium expression because it is a pure solid. The mole ratio of Co 2+ and CO3 2- is 1:1 so their molar solubilities are the same.
(2) There is an initial concentration of 0.10 M Co 2+ so write that in the "I" row for Co 2+ on the ICE table. When you find the zeros of the quadratic when solving for "s", take the positive value rather than the negative value because concentration cannot be negative.
(3) Extra products will cause the equilibrium to consume products and form reactants. So the reverse reaction will occur faster than the forward reaction. More products mean an increased Q value compared to K, since the numerator of [tex]K = \frac{[products]}{[reactants]}[/tex] increases.
How many moles of aluminum oxide will be produced from 0.50 mol of oxygen?
4 Al + 3 O2→ 2 Al2O3
Answer:
[tex]\boxed {\boxed {\sf \frac {1}{3} \ mol \ Al_2O_3 \approx 0.34 \ mol \ Al_2O_3}}[/tex]
Explanation:
We will use stoichiometry to solve this problem. The reaction given has a formula of
[tex]4Al+3O_2 \rightarrow 2Al_2O_3[/tex]
The coefficients tell us the number of moles necessary for the reaction.
The reaction requires 3 moles of oxygen to produce 2 moles of aluminum oxide. We can make a ratio.
[tex]\frac {3 \ mol \ O_2}{ 2\ mol \ Al_2O_3}}[/tex]
Since we are doing the reaction with 0.5 moles of oxygen, we multiply the ratio by that number.
[tex]0.5 \ mol \ O_2 *\frac {3 \ mol \ O_2}{ 2 \ mol \ Al_2O_3}}[/tex]
Flip the ratio so the moles of oxygen cancel each other out.
[tex]0.5 \ mol \ O_2 *\frac {2 \ mol \ Al_2O_3}{ 3 \ mol \ O_2}}[/tex]
[tex]0.5 *\frac {2 \ mol \ Al_2O_3}{ 3 }[/tex]
[tex]\frac {1 \ mol \ Al_2O_3}{ 3 }[/tex]
[tex]\frac {1}{3} \ mol \ Al_2O_3 = 0.33333 \ mol \ Al_2O_3 \approx 0.34 \ mol \ Al_2O_3[/tex]
0.5 moles of oxygen produces 1/3 or approximately 0.34 moles of aluminum oxide.
A dilute solution of hydrofluoric acid has a volume of 3.0 L and a molarity of 3.0
M. If the original solution had a volume of 2.0L, what was the initial molarity?
Answer:
4.5M
Explanation:
The solution was diluted from 2.0L to 3.0L, the dilution factor was:
3.0L / 2.0L = 1.5.
That means the solution was diluted 1.5 times.
As the final molarity of the diluted solution is 3.0M, the initial molarity of the solution was:
3.0M * 1.5 =
4.5M is the molarity of the original solutionWhat is created when an acid is mixed with a base?
Answer:
If you mix equal amounts of a strong acid and a strong base, the two chemicals essentially cancel each other out and produce a salt and water. Mixing equal amounts of a strong acid with a strong base also produces a neutral pH (pH = 7) solution.
how many atoms of carbon are in a diamond with a mass of 0.568 g?
Answer:
There are 2.85 x 10^22 atoms of carbon in a diamond with a mass of 0.568 g.
Hope this helps! :)
Calculate the pH of a solution containing 25 g of barium hydroxide (171.34 mel) dissolved in 250 mL of
solution.
Answer:
14
Explanation:
Step 1: Calculate the moles corresponding to 25 g of Ba(OH)₂
The molar mass of Ba(OH)₂ is 171.34 g/mol.
25 g × 1 mol/171.34 g = 0.15 mol
Step 2: Calculate the molar concentration of Ba(OH)₂
Molarity is equal to the moles of solute divided by the liters of solution.
[Ba(OH)₂] = 0.15 mol/0.250 L = 0.60 M
Step 3: Calculate the molar concentration of OH⁻
Ba(OH)₂ is a strong base according to the following equation.
Ba(OH)₂ ⇒ Ba²⁺ + 2 OH⁻
The molar ratio of Ba(OH)₂ to OH⁻ is 1:2. The molar concentration of OH⁻ is 2/1 × 0.60 M = 1.2 M.
Step 4: Calculate the concentration of H⁺
We will use the ionic product of water expression.
Kw = 1.0 × 10⁻¹⁴ = [H⁺] × [OH⁻]
[H⁺] = 1.0 × 10⁻¹⁴/[OH⁻] = 1.0 × 10⁻¹⁴/1.2 = 8.3 × 10⁻¹⁵ M
Step 5: Calculate the pH of the solution
We will use the definition of pH.
pH = -log [H⁺] = -log 8.3 × 10⁻¹⁵ = 14
Ms. Fremont spent last weekend grading tests . If she spent 4 min on each test , how many hours did it take her to grade all 74 tests ?
Answer:
about 5 hours
Explanation:
When doing this problem you mmust mulitiply 4 x 74 and divide the answer by 60 because 60=1 hour.
What is the final molarity of a solution when 250 mL H2O is added to 150 mL
0,040 M NaOH(aq)?
Answer:
0.015M is the final molarity of the NaOH solution
Explanation:
A solution of 0.040M NaOH is diluted from 150mL to 250mL + 150mL = 400mL. That means the solution is diluted:
400mL / 150mL = 2.667 times.
As the original solution has a concentration of 0.040M, the diluted solution has a concentration of:
0.040M / 2.667 =
0.015M is the final molarity of the NaOH solutionOxalic Acid, a compound found in plants and vegetables such as rhubarb, has a mass percent composition of 26.7% C, 2.24% H, and 71.1% O. Oxalic acid can interfere with respiration and cause kidney or bladder stones. If a large quantity of rhubarb leaves is ingested, the oxalic acid can be toxic. The lethal dose (LD50) in rats for oxalic acid is 375 mg/kg. Rhubarb leaves contain about 0.5% by mass of oxalic acid. (Show your work, using the insert equation tool :) What is the empirical formula of oxalic acid
Answer:
HCO₂
Explanation:
From the information given:
The mass of the elements are:
Carbon C = 26.7 g; Hydrogen H = 2.24 g Oxygen O = 71.1 g
To determine the empirical formula;
First thing is to find the numbers of moles of each atom.
For Carbon:
[tex]=26.7 \ g\times \dfrac{1 \ mol }{12.01 \ g} \\ \\ =2.22 \ mol \ of \ Carbon[/tex]
For Hydrogen:
[tex]=2.24 \ g\times \dfrac{1 \ mol }{1.008 \ g} \\ \\ =2.22 \ mol \ of \ Hydrogen[/tex]
For Oxygen:
[tex]=71.1 \ g\times \dfrac{1 \ mol }{1.008 \ g} \\ \\ =4.44 \ mol \ of \ oxygen[/tex]
Now; we use the smallest no of moles to divide the respective moles from above.
For carbon:
[tex]\dfrac{2.22 \ mol \ of \ carbon}{2.22} =1 \ mol \ of \ carbon[/tex]
For Hydrogen:
[tex]\dfrac{2.22 \ mol \ of \ carbon}{2.22} =1 \ mol \ of \ hydrogen[/tex]
For Oxygen:
[tex]\dfrac{4.44 \ mol \ of \ Oxygen}{2.22} =2 \ mol \ of \ oxygen[/tex]
Thus, the empirical formula is HCO₂
In an electrical circuit, the presence of a resistor limits the current and prevents
damage related to short circuits.
True or
False
_____________refers to the soil that is frozen solid all year round, and does not even melt in the summer.
Use this website to answer the question: https://thewildclassroom.com/biomes/artictundra-2/
Question 5 options:
verglas
glaze
permafrost
frost
Answer:
Permafrost is any part of the ground that remains completely frozen or colder
Methane and sulfur react to produce carbon disulfide (CS₂), a liquid often used in the production of cellophane.
2CH₄ + S₈ --> 2CS₂ + 4H₂S
Calculate the moles of H₂S produced when 2.25 mol S₈ is used.
Answer:
9 moles
Explanation:
The balanced chemical equation provided in this question is as follows:
2CH₄ + S₈ → 2CS₂ + 4H₂S
In accordance to the above balanced equation, 1 mole of sulphur (S8) produces 4 moles of hydrogen sulfide (H2S).
Therefore, if 2.25mol of S8 is used, 2.25 × 4 = 9 mol
9 moles of H2S is produced.
17. The equation below represents a chemical reaction that occurs in living cells.
CoH1206 + 602 -- 6002 + 6H20 + energy
How many atoms are represented in the reactants of this equation?
Answer:
36 atoms
Explanation:
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energyThe reactants are in the left side of the equation. First we determine how many atoms are there in the C₆H₁₂O₆ molecule:
6 C atoms + 12 H atoms + 6 O atoms = 24 atoms in totalThere are two atoms in a O₂ molecule, and there are 6 O₂ molecules in the equation:
2 * (6 O atoms) = 12 atoms in totalThe total number of atoms in the reactants is
24 + 12 = 36 atomsLEVEL 3
Write the correct order
of letters to the finish line.
A E B E C
Example:
ABCGH
G
H
N
eza
Not correct
Consider the reaction of tin with potassium hydroxide and water. Sn (s) 2KOH (aq) 4H2O (l) K2Sn(OH)6 (s) 2H2 (g) Determine the limiting reactant in a mixture containing 122 g of Sn, 134 g of KOH, and 63.9 g of H2O. Calculate the maximum mass (in grams) of potassium hydroxystannate, K2Sn(OH)6, that can be produced in the reaction. The limiting reactant is:
Answer:
The limiting reactant is: H₂O
265.3 g of K₂Sn(OH)₆ are formed in the reaction.
Explanation:
The reaction is:
Sn(s) + 2KOH (aq) + 4H₂O(l) → K₂Sn(OH)₆ (s) + 2H₂ (g)
The first step to solve is to determine the moles of each reactant:
We controlled that reaction is ballanced.
122 g . 1mol / 118.71g = 1.03 moles of Sn
134g . 1mol /56.1g = 2.39 moles of KOH
63.9 g .1mol /18g = 3.55 mol of water
Stoichiometry is 1:2:4.
Sn is the lowest reactant and water, the highest, but I can see, that water is the limiting.
1 mol of Sn needs 4 moles of H₂O to react
Then, 1.03 moles of Sn may react to (1.03 . 4)/1 = 4.12 moles.
We only have 3.55 moles. It's ok.
2 moles of KOH need 4 moles of H₂O to react
Then, 2.39 moles of KOH may react to (2.39 . 4) /2 = 4.78 moles.
We only have 3.55, there's no enough water.
So 4 moles of water can produce 1 mol of potassium hydroxystannate
Then, 3.55 moles of H₂O may produce (3.55 . 1)/4 = 0.8875 moles.
We convert moles to mass: 0.08875 mol . 298.91g /1mol =265.3g
Ca and F what are the name of the ionic compounds
Answer:
Calcium flouride?
Explanation:
Quite self explanatory
what do protons determine about an element
Answer:
The number of protons in one atom of an element determines the atom's identity, and the number of electrons determines its electrical charge. The atomic number tells you the number of protons in one atom of an element. It also tells you the number of electrons in a neutral atom of that element.
Explanation:
URGENT PLZ HELP
Which of the following statements is true?
a. In an endothermic process heat is transferred from the surroundings to the
system.
b. In an exothermic process heat is transferred from the surroundings to the
system.
C. The surroundings will feel cooler in an exothermic process.
d. The surroundings will feel warmer in an endothermic process.
Answer:
A.
Explanation:
In an endothermic reaction heat is applied.
In an endothermic process, heat is transferred from the surroundings to the system.
What are endothermic and exothermic processes?
An exothermic process is one that gives off heat. This heat is transferred to the surroundings. An endothermic process is one in which heat has to be supplied to the system from the surroundings.
The endothermic process is a term that describes a reaction where the system absorbs the energy from its surrounding in the form of heat. A few examples of the endothermic process are photosynthesis, evaporating liquids, melting ice, etc.
The exothermic reaction is the opposite of an endothermic reaction. It releases energy by light or heat to its surrounding. A few examples are neutralization, burning of a substance, reactions of fuels, etc.
Hence, option A is the correct answer.
Learn more about endothermic and exothermic processes here:
https://brainly.com/question/4345448
#SPJ2
Help me! Who ever gets to answer and has the best answer gets brainliest (very easy!)
Answer:
Fires --> These consume fuel and convert chemical energy stored in that fuel into thermal light and sound energy.
Decay -->The breakdown of dead plants and animals releases thermal energy.
Earth --> Thermal energy comes from deep inside and it is called geothermal energy.
What happened during the fusion reaction shown? 2H Зн 4He neutron O A. Two H nuclei fused into one He nucleus. O B. One He nucleus split into two H nuclei. O C. The nuclei that fused lost all their neutrons. D. The nuclei that fused lost some of their protons.
Answer: C.
Explanation:
two H nuclei fused into one He nucleus
Answer: A!
Explanation: just did it
How is gravity an attractive force?
To what temperature must a balloon, initially at 25°C and 2.00 L, be heated in order to have a volume of 6.00 L
Answer:
894 deg K
Explanation:
The computation is shown below:
Given that
V1 denotes the initial volume of gas = 2.00 L
T1 denotes the initial temperature of gas = 25 + 273 = 298 K
V2 denotes the final volume of gas = 6.00 L
T2 = ?
Based on the above information
Here we assume that the pressure is remain constant,
So,
V1 ÷ T1 = V2 ÷ T2
T2 = T1 × V2 ÷ V1
= (298)(6) ÷ (2)
= 894 deg K
b) Name three substances which can undergo sublimation and deposition respectively
solid carbon dioxide, iodine, arsenic, and naphthalene
Explanation:
Examples of substances that undergo sublimation
Examples of solids that sublime are dry ice (solid carbon dioxide), iodine, arsenic, and naphthalene (the stuff mothballs are made of).
plz, help me I'm so confused!
(this is also science)
Answer:
Well, there is no photo...
Explanation:
The following solutions are prepared by dissolving the requisite amount of solute in water to obtain the desired concentrations. Rank the solutions according to their respective osmotic pressures in decreasing order assuming the complete dissociation of ionic compounds. Rank from highest to lowest osmotic pressure. To rank items as equivalent, overlap them.
A. 1 M MgCl2
B. 1 M KCI
C. 1 M C12
D. H22011
1. Highest osmotic pressure
2. Lowest osmotic pressure
Answer: 1. Highest osmotic pressure : 1 M [tex]MgCl_2[/tex]
2. Lowest osmotic pressure: 1 M [tex]C_{12}H_{22}O_{11}[/tex]
Explanation:
[tex]\pi=i\times C\times R\times T[/tex]
[tex]\pi[/tex]= osmotic pressure
i = Van'T Hoff factor
C = concentration
T = Temperature
1. For 1M [tex]MgCl_2[/tex]
, i= 3 as it is a electrolyte and dissociate to give 3 ions.
[tex]MgCl_2\rightarrow Mg^{2+}+2Cl^{-}[/tex]
2. For 1 M [tex]KCl[/tex]
, i= 2 as it is a electrolyte and dissociate to give 2 ions.
[tex]KCl\rightarrow K^{+}+Cl^{-}[/tex]
3. For 1M [tex]C_{12}H_{22}O_{11}[/tex]
, i= 1 as it is a non electrolyte and do not dissociate.
Thus as vant hoff factor is highest for [tex]MgCl_2[/tex] thus osmotic pressure is highest for 1 M [tex]MgCl_2[/tex]
And as vant hoff factor is lowest for [tex]C_{12}H_{22}O_{11}[/tex] thus osmotic pressure is lowest for 1 M [tex]C_{12}H_{22}O_{11}[/tex]
PLEASE HELPPP WILL GIVE 10 PTS AND MARK BRAINIEST TO RIGHT ANSER!!!!!
Roasted coffee beans contain over_____________ chemical compounds
A) 10000000
B) 1000000
C) 1000
D) 10000
Answer:
C. 1000
l think this is correct answer
l hope it's helpful for you
Reactants for a certain reaction are combined in a solution. Which solution
would have the most successful collisions and so enable the reaction to
proceed quickly?
A. A solution at low concentration and low temperature
B. A solution at high concentration and low temperature
O C. A solution at high concentration and high temperature
D. A solution at low concentration and high temperature
The correct answer is solution B!