Answer:
7.05 × 10⁻²² nm
Explanation:
Step 1: Given and required data
Energy evolved when a mole of electrons changes between the 2 levels (E): 282 kJPlanck's constant (h): 6.63 × 10⁻³⁴ J.sSpeed of light (c): 3.00 × 10⁸ m/sStep 2: Calculate the wavelength (λ) of the light evolved
We will use Planck-Einstein's relation.
E = h × c/λ
λ = h × c/E
λ = (6.63 × 10⁻³⁴ J.s) × (3.00 × 10⁸ m/s)/(282 × 10³ J) = 7.05 × 10⁻³¹ m
We will convert λ to nm using the conversion factor 1 m = 10⁹ nm.
7.05 × 10⁻³¹ m × 10⁹ nm/1 m = 7.05 × 10⁻²² nm
Which of the following solutions is the most dilute.
a. 0.32 M
b. 1.5 M
c. 2.5 mol / L
d. 0.23 mol / L
e. 0.23 mol / L
Answer:
d and e
Explanation:
We have 5 solutions with different molar concentrations, that is, the quotient between the number of moles of solute and the liters of solution. This can be expressed as mol/L or M. The most dilute would be the one having the less number of moles of solute per liters of solution, that is, solution d or e, which have the same concentration. If we order them from the most diluted to the most concentrated, we get:
d = e < a < b < c
Gold has a very low specific heat capacity, just 0.13 J/goC. If a gold class ring has a mass of 4 grams and is heated from 0oC to 100oC, what is the amount of energy the gold class ring has absorbed? a 52 Joules b 0.325 Joules c 400 Joules d 3076.92 Joules
Answer:
a 52 Joules
Explanation:
Specific heat capacity of Au = 0.13 J/g° C
mass = 4 gram
initial temperature = 0° C
final temperature = 100° C
We are to determine the amount of energy absorbed
Using the formula:
Q = mcΔθ
Q = 4 × (0.13) J/g° C ×(100-0)
Q = 52 Joules
Which statement is true?
Answer:
A I think
Explanation:
Select the correct answer.
Using this activity chart, which reaction will happen when a piece of copper is placed in a lead nitrate solution?
A.
2Cu + 3Pb(NO3)2 3Cu(NO3)2 + 2Pb
B.
No reaction occurs.
C.
2Cu + 3Pb(NO3)2 2Cu(NO3)2 + 3Pb
D.
3Cu + 3Pb(NO3)2 3Cu(NO3)2 + 3Pb
E.
The answer cannot be determined from the information given.
Answer:
B, No reaction will occur
Explanation:
Copper as compared to lead is less reactive. This is the reason when lead is added to copper nitrate solution, it replaces the copper and itself combines with nitrate to form lead nitrate aqueous solution
Lead + Copper(II) nitrate → Copper + Lead (II) nitrate
The same is not the case when the reaction is revered i.e Cu is added to Pb NO3 solution.
Hence, option B is correct
What is the volume in liters that is needed to create a 2.3 M solution with 3.7 moles of Fe(OH)2? Round your answer to 1 decimal.
Answer:
Explanation:
Não sei desculpa
30 POINTS AND BRAINLIEST!!
Which statement is a true statement?
Group of answer choices
Extrusive igneous rocks are formed from the cooling lava that flows above the crust and Intrusive Igneous rocks are formed within the earth's interior.
Intrusive igneous rocks are formed from the cooling lava that flows above the crust and Extrusive Igneous rocks are formed within the earth's interior.
hallo! heres you answer
^Extrusive igneous rocks are formed from the cooling lava that flows above the crust and Intrusive Igneous rocks are formed within the earth's interior.^
is the correct one because
-Intrusive, or plutonic, igneous rock forms when magma is trapped deep inside the Earth. ... Intrusive rocks have a coarse grained texture.
- Extrusive Igneous Rocks: Extrusive, or volcanic, igneous rock is produced when magma exits and cools above (or very near) the Earth's surface.
conditions under which a reaction can be first order overall
A bimolecular reaction can be kinetically first order in behaviour provided one of the reactants is taken in such a large excess that its concentration may hardly change. Such a reactant will not contribute to the order. Thus, a bimolecular reaction will be of first order. These reactions are known as pseudo chemical reactions.
Why when you get out of the pool, the cement pavement is hot compared to the pool water?
Answer: Water is a much better conductor of heat than air. So when you are surrounded by water, energy can flow from your body (conduction of heat) much more quickly than it would if you were surrounded by air at the same temperature.
A solution at 25 degrees Celsius has a pH of 4.48. What is the pOH of this solution?
0.978
3.17
9.52
10.51
Answer:
The answer is C = 9.52
Explanation:
I took the test
The pOH of a solution that has a pH of 4.48 at 25°C is 9.52. Details about pH can be found below.
What is pH?pH refers to the power of hydrogen in a substance while the pOH refers to the power of hydroxyll ions. The pH of a solution ranges from 0 - 14 indicating the strength of acidity and alkalinity.
The relationship between the pH and pOH in a solution is given as follows:
pH + pOH = 14
According to this question, a solution at 25 degrees celsius has a pH of 4.48. The pOH of the solution is calculated as follows:
4.48 + pOH = 14
pOH = 14 - 4.48
pOH = 9.52
Therefore, the pOH of a solution that has a pH of 4.48 at 25°C is 9.52.
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To determine the percentage of bromide in a mixture containing a soluble bromide salt, the procedure from Experiment 10 is used except the bromide is precipitated with aqueous lead (II) nitrate, Pb(NO3)2, forming PbBr2(s). Initially, a 0.5014 g sample of an unknown bromide salt is dissolved in water. Excess Pb(NO3)2 is added to the solution to quantitatively precipitate the bromide from the solution. The resulting mixture is filtered through a piece of filter paper weighing 1.3258 g. After several days of drying, the filter paper and precipitate weighed 1.7895 g. Calculate the percent bromide in the original sample.
Answer:
40.27% Bromide in the original sample
Explanation:
The reaction of bromide ion, Br- with Pb(NO3)2 is:
2 Br- + Pb(NO3)2 → PbBr2(s)
Where the precipitate produced is PbBr2
To solve this question we must find the moles of PbBr2 filtered using its mass. Twice these moles we can find the moles of Br- and its mass. Percent bromide is:
Mass Bromide / Mass Sample (0.5014g) *100
Mass PbBr2:
1.7895g - 1.3258g = 0.4637g PbBr2
Moles -Molar mass: 367.01g/mol-
0.4637g PbBr2 * (1mol / 367.01g) =
0.001263 moles PbBr2 * (2mol Br / 1mol PbBr2) = 0.002527 moles Br
Mass Br -Molar mass: 79.904g/mol-
0.002527 moles Br * (79.904g / mol) =
0.2019g Br
Percent Bromide:
0.2019g Br / 0.5014g * 100 =
40.27% Bromide in the original sampleHow many liters of a 0.689 M solution of NaCl would contain 75 g of NaCl?
Answer:
E) the K+ ions are attracted to the partially positive hydrogen atoms of the water molecule. D) the K+ ions are attracted to the partially negative oxygen atoms of the water molecule. Water is a polar solvent and hexane (C6H14) is a nonpolar solvent. Which of the following correctly describes the solubility of the solute? A) weak electrolyte.
Explanation:
A student is trying to develop questions to help identify an unknown biome. Which of the following questions would provide helpful information to identify an unknown biome? Select ALL that apply. A. Is sunlight an abiotic factor in this biome? B. What is the average temperature of this biome? C. How much precipitation does this biome receive each year? D. What adaptations do plants and animals have to survive in this biome? E. Is the biome located near an ocean? F. Do plants and animals live in this biome? G. Does carbon cycle in this biome?
Answer:
I think the answer is C. D. And F.
Explanation:
I’m sorry if I’m wrong :(
Answer:
I think the answer is BCD and maybe F
Explanation:
A gas has a solubility of 2.45 g/L at a pressure of 0.750 atm. What pressure wold be required to produce an aqueous solution containing 6.25 g/L of this gas at constant temperature
Answer:
1.91 atm
Explanation:
Step 1: Calculate Henry's constant (k)
A gas has a solubility (C) of 2.45 g/L at a pressure (P) of 0.750 atm. These two variables are related to each other through Henry's law.
C = k × P
K = C/P
K = (2.45 g/L)/0.750 atm = 3.27 g/L.atm
Step 2: Calculate the pressure required to produce an aqueous solution containing 6.25 g/L of this gas at constant temperature.
We have C = 6.25 g/L and k = 3.27 g/L.atm. The required pressure is:
C = k × P
P = C/k
P = (6.25 g/L)/(3.27 g/L.atm) = 1.91 atm
Sea turtles use the earths geomagnetic field to navigate their way home. What is the reason earth has a geomagnetic filed?
Answer:
::Due to the iron inside the earth.
Explanation:
Imagine a sphere of Iron, as big as two-third the size of the moon and as hot as 5700 Kelvin. That is the Earth’s core.
The iron core isn't in its liquid form even at that temperature because it is crushed under immense gravity. This core is surrounded by 2000 km of other metals like iron and nickel which are in their molten state.
The temperature is not the same at every point in this molten layer. The hotter and less dense matter rises up, and the warm denser matter sinks. This causes convectional currents in the interior of the Earth.
Because of the Earth’s spin, there is a force that established called the Coriolis force which causes swirling whirlpools here too.
This flow of molten metals produces electric currents which generate self-sustaining magnetic fields. And as a result of the Coriolis force, all these combined effects add up to produce one big magnetic field engulfing the Earth aligned in one direction.
Why do some states have more representatives than other states? A Because states have different land areasBecause states have different land areas B Because states joined the U.S. in different yearsBecause states joined the U.S. in different years C Because all states have the same number of representativesBecause all states have the same number of representatives D Because states have different populationsBecause states have different populations
Answer:
D
Explanation:
The number of representatives depends on the population size. A state with fewer residents will have less representatives than a state with more residents.
1.6 x 1023 atoms of Be, how many moles of Be are there?
Answer:
1 mole.
Explanation:
1.6x10^23 = NA = 1 mole of any substance.
Lab 6: Basic Chemistry Thermodynamics: Solve the challenge of storing renewable energy
Answer:
Expensive and low storing capacity.
Explanation:
The storing of renewable energy is a big challenge for us because this renewable energy can't be stored for a long due to expensive and low storing capacity. There are two challenges about the storing of renewable energy is that the battery are very expensive and can store very less amount of energy which makes unable to store the renewable energy. The scientists should make a storing device which is not too much expensive and has more storage capacity.
What is the reason for heat transfer from one substance to another?
Answer:
Difference in temperature
Explanation:
According to thermodynamics, heat transfer occurs when heat from a high temperature reservoir moves to a low temperature reservoir. For heat to be transferred, the two objects should have different temperatures with one having more temperature than the other. Heat transfer in solids is by conduction, in fluids is by convection and by radiation.
Which atoms are most likely to form + 1 ion and -2 ion respectively?
a. Sr and S
b. Kand o
C. Fe and N
d. Ba and F
When does phenolphthalein turn pink?
in the presence of a base
in the presence of an acid
when it is in a neutral solution
when it is reacting with a metal
Answer:
A. In the Presense of a base
Explanation:
Just took the test from Edgunuity
Phenolphthalein turns pink in color in the presence of a base. Therefore, option A is correct.
What is phenolphthalein and its use?Phenolphthalein is a chemical compound that is often used as an acid-base indicator. It is colorless in acidic solutions and pink or red in basic solutions.
Phenolphthalein is often used in titrations to determine the endpoint of a reaction between an acid and a base. It can also be used as a laxative or in forensic investigations to test for the presence of blood.
Phenolphthalein has a chemical formula of C₂₀H₁₄O₄ and is synthesized by reacting phthalic anhydride with phenol in the presence of a strong acid catalyst. It is also used as a pH indicator. phenolphthalein has been found to have potential health benefits, such as reducing the risk of cancer, improving digestion, and reducing inflammation. Therefore, option A is correct.
Learn more about phenolphthalein, here:
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Magma forms within the mantle as a result of _______ temperature and _______ pressure.
All rocks are made of ___________
Answer:
extreme/high
low
minerals
Explanation:
When Magma forms within the mantle what is the most often result? The most often result of this is high temperatures, and low pressure.
The candle is lit and dilute ethanoic acid is poured down the inside of the beaker. As the acid reacts with the baking soda, bubbles of CO2 gas form. After a few seconds
the air in the beaker is replaced by 0.20 liter of CO2 gas, causing candle flame to go out. The density of CO2 gas is 1.8 grams per liter at room temperature.
Choose the correct structural formula for the acid that was poured into the beaker.
Answer:
It’s answer #2
Explanation:
I only know this because i just got it wrong
The correct structural formula for the acid that is poured into the beaker is CH₃COOH.
What is acetic acid?Acetic acid is also called ethanoic acid. It is form as a byproduct of fermentation. It forms vinegar. Vinegar is 4 to 6% acetic acid with water.
It is widely used in homes as cleaning agent, in cooking, washing etc.
Thus, the correct option is 2, CH₃COOH.
Learn more about acetic acid
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Calculate the number of molecules present in .20 moles of H2O
Answer:
Number of moles =20
Number of molecules present = 20 multipled by avogadro's number.
Identify whether each compound is a straight chain, branched chain, or cycloalkane.
ОН
сн.
CH,
ж
E
НО шин-
-- ОН
нс
НО
"ОН
Answer:
Branched chain
Cycloalkane
Straight chain
Explanation:
V2O5 + Ca = V + CaO balance the eqaution
Answer: The balanced equation is [tex]V_{2}O_{5} + 5Ca \rightarrow 2V + 5CaO[/tex].
Explanation:
A chemical equation which contains same number of atoms on both reactant and product side is called a balanced chemical equation.
For example, [tex]V_{2}O_{5} + Ca \rightarrow V + CaO[/tex]
Here, number of atoms on reactant side are as follows.
V = 2O = 5Ca = 1The number of atoms on product side are as follows.
V = 1O = 1Ca = 1In order to balance this equation, multiply Ca by 5 on reactant side. Multiply V by 2 and CaO by 5 on product side. Therefore, the equation can be rewritten as follows.
[tex]V_{2}O_{5} + 5Ca \rightarrow 2V + 5CaO[/tex]
Now here, number of atoms on reactant side are as follows.
V = 2O = 5Ca = 5The number of atoms on product side are as follows.
V = 2O = 5Ca = 5Since, there are same number of atoms on both reactant and product side. So, the equation is now balanced.
Thus, we can conclude that the balanced equation is [tex]V_{2}O_{5} + 5Ca \rightarrow 2V + 5CaO[/tex].
In order to use the Ideal Gas Constant of 0.0821, what units must be used for volume, pressure, amount, and temperature?
Answer:
The value becomes 0.0821 L-atm/K⁻¹-mol⁻¹.
Explanation:
The value of gas constant is 0.0821.
We know that, the ideal gas law is as follows :
[tex]PV=nRT\\\\R=\dfrac{PV}{nT}[/tex]
Where
P is pressure
V is volume
T is temperature
In order to use the Ideal Gas Constant of 0.0821, the units are follows :
Volume = Litre (L)
Pressure = atm
Amount = mol⁻¹
Temperature = K⁻¹
So, the value becomes 0.0821 L-atm/K⁻¹-mol⁻¹.
What type of bond will be formed between Ar and Cu
If 0.60 L of a solution contains 6.6 g of NaBr, what is its molar concentration?
Answer:
Molarity = moles ÷ liters
to get moles of NaBr divide grams of NaBr by its molar mass (mass of Na + mass of Bromine)
Na = 22.989769
Br = 79.904
molar mass of NaBr = 102.893769
6.6g ÷ 102.893769 = 0.064143826 moles of NaBr
0.064143826 moles ÷ 0.60 liters = 0.1069 molar concentration or 11 %
PLEASE HELP!!! CHEMISTRY
Which one would require more energy to overcome because it is the strongest? Hydrogen bonding or van der waals?
Which of the following particles have the same mass. Proton, Neutron, Electron, None
Answer: proton and neutron
Explanation:
They both have the mass of 1