Answer:
a. 28.5 min
Explanation:
The computation of the number of minutes would it take to plate out is as follows:
Cu+2 +2e [tex]\rightarrow[/tex]Cu
The two moles of electrons could be generated for the copper i.e. deposited
Now
moles of copper is
= 4.5 ÷ 63.5
= 0.071
The 63.5 represents the atomic copper weight
Now mole of electrons deposited is
= 0.071 × 2
= 0.142
Now
quantitiy of electricity needed
= moles of electrons deposited × 96500
= 0.142 × 96500
= 13703 coulums
As per electricity quantity needed
= current × time(seconds)
= 13703 = 8 × t
t = 13703 ÷ 8
= 1713 seconds
= 1713 ÷ 60 minutes
=28.5 min
hence, the correct option is a.
Match the definition with the correct term: 1/12th the mass of a carbon-12 atom.
Answer:
hydrogen atom but see the note below.
Explanation:
This is either the most common hydrogen ion or a hydrogen atom. It cannot be either of hydrogen's isotopes.
Use scientific notation to express the number 355000 to:
1) one significant figure
2) two significant figures
3) three significant figures
4) four significant figures
5) six significant figures
Answer:
1) 4*10^5
2) 3.6*10^5
3) 3.55*10^5
4) 3.550*10^5
5) 3.55000*10^5
Explanation:
1) 4 x [tex]10^5[/tex]
2) 3.6 x [tex]10^5[/tex]
3) 3.55 x [tex]10^5[/tex]
4) 3.550 x [tex]10^5[/tex]
5) 3.55000 x [tex]10^5[/tex]
What is scientific notation?A number is written in scientific notation when there is a number greater than or equal to 1 1 11 but less than 10 10 1010 multiplied by a power of 10 10.
Significant figures are the number of digits in a value, often a measurement, that contributes to the degree of accuracy of the value.
1) 4 x [tex]10^5[/tex]
2) 3.6 x [tex]10^5[/tex]
3) 3.55 x [tex]10^5[/tex]
4) 3.550 x [tex]10^5[/tex]
5) 3.55000 x [tex]10^5[/tex]
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The phase change between white tin and gray tin is difficult to observe directly. Both substances can be burned, however. From these equations, calculate AHⓇ for the conversion of gray tin into white tin:
Sn(s, white) + O2(g) + SnO2(g) AH = -580.69 kJ
Sn(s, gray) + O2(g) + SnO2(g) AH° = -582.78 kJ
AH = _________ kJ
Answer: Thus [tex]\Delta H[/tex] for the conversion of gray tin to white tin is -20.9 kJ
Explanation:
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The final reaction is
[tex]Sn(s, gray)\rightarrow Sn(s, white)[/tex] [tex]\Delta H=?[/tex]
The intermediate balanced chemical reaction will be,
[tex]Sn(s, gray)+O_2(g)\rightarrow SnO_2(g)[/tex] [tex]\Delta H^0=-582.78kJ[/tex] (1)
[tex]Sn(s, white)+O_2(g)\rightarrow SnO_2(g)[/tex] [tex]\Delta H^0=-580.69kJ[/tex] (2)
substarcting (2) form (1) we get
[tex]\Delta H=\Delta H_1-\Delta H_2[/tex]
[tex]\Delta H=-582.78-(-580.69kJ)[/tex]
[tex]\Delta H=-20.9kJ[/tex]
6. If you 5.5 mol of Nitrogen in: N2 + 3H2 → 2NH3
a. How many moles of Hydrogen are needed to completely react with the nitrogen?
b. How many moles of Ammonia will be produced?
Answer:
Therefore 9 moles of nitrogen are required to produce 18 moles of ammonia.
consider the reaction between acetylene C2H2 and oxygen in a welding torch 2C2H2 + 5O2 = 4CO2 + 2H2O of 5.4 moles of acetylene react with sufficient oxygen how many grams of CO2 should form
Answer:
C. 4.8*10² g.
Explanation:
A system gains 687 kJ of heat, resulting in a change in internal energy of the system equal to 156 kJ. How much work is done?
1. Work was done by the system.2. Work was done on the system.
Answer:
w = -531 kJ
1. Work was done by the system.
Explanation:
Step 1: Given data
Heat gained by the system (q): 687 kJ (By convention, when the system absorbs heat, q > 0).Change in the internal energy of the system (ΔU°): 156 kJStep 2: Calculate the work done (w)
We will use the following expression.
ΔU° = q + w
w = ΔU° - q
w = 156 kJ - 687 kJ
w = -531 kJ
By convention, when w < 0, work is done by the system on the surroundings.
) How many moles are there in 2.00 x 10^19 molecules of calcium phosphate?
Answer:
[tex] \huge 3.322 \times {10}^{ - 5} \: \: moles \\ [/tex]
Explanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{2.00 \times {10}^{19} }{6.02 \times {10}^{23} } \\ \\ = 3.322 \times {10}^{ - 5} \: \: moles[/tex]
Hope this helps you
How many mL of O2 at STP are produced from 1.5 g KClO3
Answer:
64.2 L
i watch videos about this stuff because my grades were very low now im bringing the up
Explanation:
In order to be able to calculate the volume of oxygen gas produced by this reaction, you need to know the conditions for pressure and temperature.
Since no mention of those conditions was made, I'll assume that the reaction takes place at STP, Standard Temperature and Pressure.
STP conditions are defined as a pressure of
100 kPa
and a temperature of 0∘C
. Under these conditions for pressure and temperature, one mole of any ideal gas occupies
22.7 L
- this is known as the molar volume of a gas at STP.
So, in order to find the volume of oxygen gas at STP, you need to know how many moles of oxygen are produced by this reaction.
The balanced chemical equation for this decomposition reaction looks like this
2KClO3(s]heat×−−−→2KCl(s]+3O2(g]↑⏐
please help this makes no sense to me!!
Answer:
potassium nitrate= KNO3 ---> KNO2 + O2 and a gas evolution reaction
Explanation:
i think
Andesitic rock is an igneous rock with a composition in between that of basaltic and granitic igneous rock.
true or false
Answer:
Explanation:
intristing
Your aunt is sipping on iced tea and fanning herself during a hot South Carolina summer day. You tell her that there is enough energy in one drop of her iced tea to run the air conditioner for the rest of her life if the energy could be extracted with 100% efficiency. Your aunt asks you to explain. Use the concepts you learned in this unit to explain the relationship between forces, energy, and matter.
Answer:
Isn't this like having enough energy to supply the world for centuries with just 1% of the sea's force?
Explanation:
I guess it's because the amount of energy in it can supply energy.
Adaleigh is learning about renewable and non-renewable resources in her science class. She decides to take
a nature walk and makes notes of all the renewable resources that she sees. Which of the following is an
observation that Adaleigh could have made on her walk?
A. The seeds on the ground are going to grow into new trees.
B. The tallest trees had the most seeds around their bases.
C. When trees decay, they could eventually turn into coal.
D. Pine trees are older than oak trees.
Answer:
A. The seeds on the ground are going to grow into new trees.
Explanation:
Trees are renewable resources.
A 25 cm sample of dilute sulfuric acid contains 0.025 moles of the acid.
What is the hydrogen ion concentration in the solution?
A. 0.2 mol/dm3
B. 0.05 mol/dm3
C. 1.00 mol/dm3
D. 2.00 mol/dm3
Answer:B. 0.05 mol/dm3
Explanation:
The hydrogen ion concentration in the solution is 2 mol/dm³
The correct answer to the question is Option D. 2 mol/dm³
We'll begin by calculating the molarity of the solution.
Volume = 25 cm³ = 25 / 1000 = 0.025 dm3
Mole of H₂SO₄ = 0.025 mol
Molarity of H₂SO₄ =?Molarity = mole / Volume
Molarity of H₂SO₄ = 0.025 / 0.025
Molarity of H₂SO₄ = 1 mol/dm³Finally, we shall determine the concentration of Hydrogen ion in the solution.H₂SO₄(aq) —> 2H⁺(aq) + SO₄²¯(aq)
From the balanced equation above,
1 mole of H₂SO₄ contains 2 moles of H⁺.
Therefore,
1 mol/dm³ H₂SO₄ will also contain 2 mol/dm³ H⁺.
Thus, the concentration of Hydrogen ion in the solution is 2 mol/dm³
The correct answer to the question is Option D. 2 mol/dm³
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There are 20 mice in a 5 m2 field ecosystem. The population density of mice is _____.
20 per m 2
5 per m 2
25 per m 2
4 per m 2
Answer:
4per m 2
20 mice divided by 5 so it will be 4 per m 2
True or False
ATP energy is used to move muscles and build protein in your body
If a cell has waste it needs to store, it will store it:
Answer:
The vacuole is the storage area of the cell. Most cells have one large vacuole. Vacuoles store food and other materials needed by the cell. They can also store waste products.
Explanation:
In an experiment, two unknown compounds (one an ether and the other an amine) of equal molecular mass were dissolved in water. The result of the experiment is shown in the table.
Solubility Comparison
Unknown Compound Solubility (g/100 ml water)
A 4
B 0.25
Which of the following correctly explains the identity of Compound A and its solubility?
It is an amine; it contains a nitrogen atom that will allow nitrogen-hydrogen bonds to form while in water.
It is an ether; because the oxygen atom is within the carbon chain, so it is free to form oxy-hydrogen bonds to make it more soluble.
It is an ether; the high polarity of the oxygen-hydrogen bond makes it more soluble.
It is an amine; because the lower electronegativity of N than H makes it more soluble.
Answer:
It is an amine; it contains a nitrogen atom that will allow nitrogen-hydrogen bonds to form while in water.
Explanation:
The solubility of amines owes largely to the electronegativity difference between nitrogen and hydrogen. Remember that when hydrogen is bonded to highly electronegative element such as nitrogen, intermolecular hydrogen bonding is possible with water molecules. This explains the greater solubility of amines in water.
Ether molecules do have an oxygen atom, however, and engage in hydrogen bonding with water molecules to a lesser extent compared to amines.
Also, amines participate in some acid-base reactions that lead to the formation of diethylammonium hydroxide, an ion which leads to a greater solubility of amines compared to an ether.
Hence, compound A is an amine.
Andesitic rock is an igneous rock with a composition in between that of basaltic and granitic igneous rock.
true or false
An atom of which element has the strongest attraction for the electrons in a bond?
a. aluminum
b. carbon
c. chlorine
d. lithium
Answer:
chlorine
Explanation:
This is because the electronegativity increases from left to right and decreases from top to bottom of the periodic table.
A complex absorbs photons with an energy of 4.10×10^−19 J. What is the wavelength of these photons? If this is the only place in the visible spectrum where the complex absorbs light, what color would you expect the complex to be?
Answer:
483 nm corresponds to blue light hence the complex will appear orange.
Explanation:
Using the formula;
E= hc/λ
Where;
E = energy of the photon
h = Plank's constant (6.6*10^-34Js)
c = Speed of light (3*10^8 ms-1)
λ = wavelength
λ = hc/E
λ = 6.6*10^-34 * 3*10^8/4.10×10^−19
λ = 4.83 * 10^-7 or 483 nm
483 nm corresponds to blue light
Using the colour wheel approach, if a complex absorbs blue light, then it will appear orange.
A current of 5.29 A is passed through a Sn(NO3)2 solution for 1.30 h . How much tin is plated out of the solution?
Answer:
15.26 g of tin
Explanation:
Given that the equation of the process is;
Sn^2+(aq) + 2e ------> Sn(s)
Since 1e = 1F= 96500 C
but q =It
t is in hours so it must be converted to seconds, the SI unit of time
Hence;
119g of tin is deposited by 2 * 96500 C
xg of tin is deposited by 5.29 * 1.30 * 60 * 60
x = 119 * 5.29 * 1.30 * 60 * 60/ 2 * 96500
x = 2946106.8/193000
x= 15.26 g of tin
A current of 5.29 A is passed through a Sn(NO₃)₂ solution for 1.30 hour, the amount of tin plated is 15.26 grams.
How do we calculate mass?Mass of any deposited susbatnce that is obtained by the passing of current will be calculated by using the Faraday's Law as:
W = ECT/F, where
W = required mass of deposited tin
C = current = 5.29 A
T = time period = 1.30hr = 4,680sec
F = faradays constant = 96500C
E = equivalent mass
Equivalent mass will be calculated as:
E = molar mass/charge on atom = 119/2 = 59.5 g/equ
On putting all these values in the above equation, we get
W = (59.5)(5.29)(4680) / 96500
W = 15.26 g
Hence mass of tin is 15.26 g.
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Plzzzz help right answer gets a brainly!
Answer: 4
Explanation: Your counting 4 for each interval. 9+4 =13 13+4 =17 17+4 =21 and so on.
what are 4 sources of electrical energy?
Answer:
Clean Energy. Learn more about energy from solar, wind, water, geothermal, biomass and nuclear. Fossil. Learn more about our fossil energy sources: coal, oil and natural gas.Electric Power. Learn more about how we use electricity as an energy source. Energy Storage. Hydrogen & Fuel Cells.Explanation:
I hope this helps xD
Answer:
Electrical energy is used to power up a light bulb. The current moves from the outlet to the light bulb through the wire.
Lightning is another example of electrical energy. The negatively charged particles are separated from the positively...
Batteries are also sources of electrical energy. In car batteries, the moving charges Explanation:
fI gave u 3 think of the 4th one
Calculate the amount of heat, in Joules, needed to raise 34.0g of water from 55.0°C to 76.0*C. The specific heat of water is 4.18 J/gºC.
Answer:
2984.52J
Explanation:
Using the formula: Q = m × c × ∆T
Where;
Q = amount of heat (in Joules)
m = mass (in grams)
c = specific heat capacity (J/g°C)
∆T = change in temperature (°C)
Based on the information provided in the question;
m = 34.0g
c = 4.18 J/gºC.
Initial temperature = 55.0°C
Final temperature = 76.0°C
Hence, Q = m × c × ∆T
Q = 34 × 4.18 × (76 - 55)
Q = 142.12 × 21
Q = 2984.52J
Therefore, 2984.52J is the amount of heat, in Joules, needed to raise 34.0g of the water.
FeO+ PdF2 ---> FeF2+PdO balance please worth 50 points
Answer: FeO
Explanation:
Answer:
This is not worth 50 points liar
Explanation:
What are homogeneous mixture and heterogeneous mixture ?
Explanation:
"A homogeneous mixture has the same proportions of its components throughout any given sample and is also referred to as a solution. Conversely, a heterogeneous mixture has components of which proportions vary throughout the sample."
- Wikipedia
17 Which changes decrease the rate of reaction between magnesium and air?
1.heating the magnesium to a higher temperature
2.using a higher proportion of oxygen in the air
3.using magnesium ribbon instead of powdered magnesium
A 1, 2 and 3
B 1 only
C 2 only
D 3 only
Using magnesium ribbon instead of powdered magnesium decrease the rate of reaction between magnesium and air.
What is rate of reaction?Rate of reaction tells about the duration of the completion of the reaction.
Rate of any reaction is directly proportional to the concentration and surface area of the reactant, temperature, catalyst, no. of collision, activation energy, etc.
So, if we magnesium in the ribbon instead of powdered magnesium the surface area of the reactant side decreases which results in the decrease of the rate of reaction.
Hence, option (D) is correct i.e. rate of reaction decreases on using magnesium ribbon instead of powdered magnesium.
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Select the correct answer.
Which equation correctly relates kinetic energy, mass, and velocity?
OA. KE=3m22
OB. KE = mv2
Oc. KE=mu
OD. KE = mv3
Answer:
Ke1/2mv2
Explanation:
Hope this helps
Answer:
KE 1/2 MV2
ExplanationExplanationExplanationExplanation: hope this helps
Which of the following processes occurs when wind and water move weathered and eroded pieces away from rock? *
A. Cementation
B: Deposition
C: Transportation
D: Consolidation
Answer:
lemme guess is it transportation??
Help pleaseeeeeeeee with this question
Answer:
(C) Vacuum
Explanation:
