Answer:
B
Explanation:
took the test
D. It should have a half-life much longer than the age of the object being dated. When using isotopes for dating purposes, it is important to choose an isotope with a half-life that is significantly longer than the age of the object being dated.
What is the half-life time?The half-life is the time it takes for half of the radioactive isotopes in a sample to decay into stable isotopes. By measuring the ratio of the original radioactive isotope to the decay product, scientists can determine the age of the object.
The majority of the radioactive material would have decayed if the isotope had a half-life substantially less than the age of the artefact, making it challenging to precisely establish the age.
On the other hand, the dating procedure would become more challenging and unpredictable if the isotope in the object being dated (option C) has a half-life that varies over time.
As a result, an isotope with a long half-life offers a stronger basis for precise dating since it enables sufficient radioactive decay to take place, producing quantifiable and trustworthy data.
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Jim makes a mixture which contains 10 mg of salt, 30 mg of sand, and some iron filings. The total mass of the mixture is 100 mg
Which amount of iron filings does Jim use in the mixture?
A10
B30
C40
D60
Answer:
Amount of iron fillings in mixture = 60 mg
Explanation:
Given:
Total mass of mixture = 100 mg
Amount of salt in mixture = 10 mg
Amount of sand in mixture = 30 mg
Find:
Amount of iron fillings in mixture
Computation:
Using Law of Conservation of mass;
Total mass of mixture = Amount of salt in mixture + Amount of sand in mixture + Amount of iron fillings in mixture
100 = 10 + 30 + Amount of iron fillings in mixture
100 = 40 + Amount of iron fillings in mixture
Amount of iron fillings in mixture = 100 - 40
Amount of iron fillings in mixture = 60 mg
can someone answer this
12 moles of sodium into grams
Answer:
12 moles sodium= 275.87724000000003 grams
Explanation:
1 moles sodium = 0.043497607849056.
On the basis of the information above, what is the approximate percent ionization of HNO2 in a 1.0 M HNO2 (aq) solution?
Answer:
The answer is "2%"
Explanation:
Equation:
[tex]HNO_2\ (aq) \leftrightharpoons H^{+} \ (aq) + NO_2^{-}\ (aq) \\\\\ K_a = 4.0\times \ 10^{-4}[/tex]
[tex]H^{+}=?[/tex]
Formula:
[tex]Ka = \frac{[H^{+}][NO_2^{-}]}{[HNO_2]}[/tex]
Let
[tex][H^{+}] = [NO_2^{-}] = x[/tex] at equilibrium
[tex]x^2 = (4.0\times 10^{-4})\times 1.0\\\\x = ((4.0\times 10^{-4})\times 1.0)^{0.5} = 2.0 \times 10^{-2} \ M\\\\[/tex]
therefore,
[tex][H^{+}] = 2.0\times 10^{-2} \ M = 0.02 \ M[/tex]
Calculating the % ionization:
[tex]= \frac{([H^{+}]}{[HNO_2])} \times 100 \\\\= \frac{0.02}{1}\times 100 \\\\= 2\%\\\\[/tex]
The approximate percent ionization of HNO₂ in a 1.0 M HNO₂ (aq) solution is 2%.
How we calculate the % ionization?% ionization of any compound will be calculated as follow:
% ionization = ([ion]/[acid or base]) ₓ 100
Given chemical reaction with ICE table will be represented as:
HNO₂(aq) → H⁺(aq) + NO₂⁻(aq)
initial 1 0 0
change -x +x +x
equilibrium 1-x x x
Equilibrium constant will be represented as:
Ka = [H⁺][NO₂⁻] / [HNO₂]
Acid dissociation constant for HNO₂ = 4×10⁻⁴
Putting all values in the above equation, we get
4×10⁻⁴ = x² / 1-x
Value of changeable quantity is very less, so we neglect from the concentration of HNO₂.
4×10⁻⁴ = x²
x = 2 × 10⁻²
So, the concentration of H⁺ ion = 2 × 10⁻²M
Now we put all these values in the % ionization equation, we get
% ionization = (0.02/1) × 100 = 2%
Hence , % ionization is 2%.
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A certain reaction has an activation energy of 51.02 kJ/mol. At what Kelvin temperature will the reaction proceed 4.50 times faster than it did at 365 K
Answer:
[tex]T_2=400.73K[/tex]
Explanation:
From the question we are told that:
Activation energy [tex]E_a= 51.02 kJ/mol.=>51.02*10^3J/mol[/tex]
Reaction Ratio [tex]\triangle K=4.50[/tex]
Initial Temperature [tex]T_1=365K[/tex]
Generally the equation for Final Temperature [tex]T_2[/tex] is mathematically given by
[tex]log \triangle K=\frac{E_a}{2.303R}*(\frac{T_2-T_1}{T_1T_2})[/tex]
Where
[tex]R=Gas constant[/tex]
[tex]R =8.3143[/tex]
Therefore
[tex]log 4.50=\frac{51.2*10^3}{2.303*8.31432}*(\frac{T_2-365}{365*T_2})[/tex]
[tex]log 4.50=7.328*\frac{T_2-365}{T_2}[/tex]
[tex]0.0892=\frac{T_2-365}{T_2}[/tex]
[tex]0.0892T_2=T_2-365[/tex]
[tex]365=T_2-0.0892T_2[/tex]
[tex]365=0.91T_2[/tex]
[tex]T_2=\frac{365}{0.91}[/tex]
[tex]T_2=400.73K[/tex]
Ammonia will decompose into nitrogen and hydrogen at high temperature. An industrial chemist studying this reaction fills a 5.0L flask with 4.5 atm of ammonia gas, and when the mixture has come to equilibrium measures the amount of nitrogen gas to be 1.1 atm. Calculate the pressure equilibrium constant for the decomposition of ammonia at the final temperature of the mixture. Round your answer to 2 significant digits.
Answer:
Kp = 7.4727
Explanation:
Let's write the balanced equilibrium reaction:
2NH₃ <-------> N₂ + 3H₂ Kp = ??
Now, if we want to calculate the Kp, we need to write an ICE chart with this reaction, which is the following:
2NH₃ <-------> N₂ + 3H₂
I. 4,5 0 0
C. -2x +x +3x
E. 4,5-2x x 3x
According to this chart, the Kp expression should be:
Kp = (PH₂)³ * (PN₂) / (PNH₃)² (1)
The value of x, we already know it because the problem states that the amount of nitrogen gas is 1.1 atm, so replacing this value into (1) we have:
Kp = (3*1.1)³ * (1.1) / (4.5 - (2 * 1.1))²
Kp = 39.5307 / 5.29
Kp = 7.4727Hope this helps
Determine the number of molecules of C2CI4 contained in 73.1g of C2CI4
Answer:
2.35x10²³ molecules of C2Cl4 are present
Explanation:
To solve this question we must convert, as first, the mass of C2Cl4 to moles using its molar mass (C2Cl4 = 165.83g/mol). Then, using Avogadro's number we can find the number of molecules:
Moles C2Cl4:
73.1g * (1mol / 165.83g) = 0.441 moles C2Cl4
Molecules:
0.441 moles C2Cl4 * (6.022x10²³molecules / 1mol) =
2.35x10²³ molecules of C2Cl4 are presentGiven the reaction: N2(g) +2O2(g) ⇌ 2NO2(g) The forward reaction is endothermic. Determine which of the following changes would result in more product being produced.
I. Increase NO2
II. Decrease O2
III. Add a catalyst
IV. Increase the temperature
V. Increase the pressure
A. I and II
B. II, III, and V
C. IV and V
D. II and IV
Answer:
C
Explanation:
increasing the temperature will favour the forward reaction therefore the reaction system will try to counteract that by producing more heat and NO2 therefore increases the amount of products produced
increasing the pressure will favour the forward reaction as it has more moles of substance therefore if the forward reaction is favored, more product will be produced
Answer:
C.) lV and V
Explanation:
I got it correct on founders edtell
What is the initial and final mass of the zinc and copper?
Answer:the final mass of copper is 3.84 g. There was an increase in mass of 1.84 g from the initial mass of 2.0 g.
Explanation:
What volume is occupied by 2.0 mol of gas at 3.0 atm
and 27 °C?
Calculate the specific heat of a substance given that 49 joules of heat is required to raise the temperature of 25.0 g of the substance from 92.6 ºC to 99.4 ºC.
Answer:
0.29 J/g.°C
Explanation:
Step 1: Given data
Added heat (Q): 49 JMass of the substance (m): 25.0 gInitial temperature: 92.6 °CFinal temperature: 99.4 °CStep 2: Calculate the temperature change (ΔT)
ΔT = 99.4 °C - 92.6 °C = 6.8 °C
Step 3: Calculate the specific heat of the substance (c)
We will use the following expression.
Q = c × m × ΔT
c = Q / m × ΔT
c = 49 J / 25.0 g × 6.8 °C = 0.29 J/g.°C
What is the IUPAC name for the following compound?
a. benzenecarbonitrile
b. benzenecyanide
c. phenylcyanide
d. cyanophenyl
Answer:
Option a. Benzenecarbonitrile
Explanation:
You are not providing the picture of the compound. However, I manage to find the picture of it, so I'm gonna answer this with the picture. Its attached here at the end.
As for the IUPAC name of this compound, it would be Benzenecarbonitrile, or simply, benzonitrile.
This compound has the molecular formula C₆H₅CN. It receives this name over the other ones, because this is a aromatic cyanide, and aromatic cyanide has nitriles behavior, (Strength of the nitrogen over the carbon), therefore, this group has priority over the whole molecule. As the principal chain is the benzene, the carbonitrile is the radical of the group, and when cyano groups are as radical and not as principal chains, it has a behavior of nitrile, and it's named as nitrile. therefore, option b, cannot be the name.
phenylcyanide is naming the phenyl as radical, but the benzene is the principal group in this compound, and the cyanide is the radical. It happens the same thing with cyanophenyl.
Hope this helps
Which best describes the total mass of substances before and after a
combustion reaction?
A. The mass is the same because atoms are not created or
destroyed.
B. The mass is greater after the reaction because the number of
atoms increases.
C. The mass is the same because the molecules do not change.
D. The mass is less after the reaction because gases are produced.
Answer:
B. The mass is greater after the reaction because the number of
atoms increases.
What answer is it and how ? please help !!!!!! ill mark brainlyest if right
Answer:
The answer is B
Brainliest please!
Help solve the types of chemical reactions
[tex]1) \: decomposition[/tex]
[tex]2) \:hydrocarbon \: combustion[/tex]
[tex]3) \: formation[/tex]
[tex]4) \: double - replacement[/tex]
[tex]5 \: double - replacement[/tex]
[tex]6) \: formation[/tex]
[tex]7)double \: - replacement[/tex]
[tex]8) \: double - replacement[/tex]
Read about reverse osmosis and multistage flash distillation .Then identify at least three advantages and three
disadvantages for each process
Answer:
Meaning, Advantages & Disadvantages of - Osmosis, Multiflash Distillatiob
Explanation:
Osmosis is movement of solvent (like water) through semi permeable membrane (like living cell) into solution of higher solute concentration.Advantages - It assists equalising concentration of solute on two sides of membrane. Reverse Osmosis is used for efficient water softening, it is easy to maintain.
Disadvantages - It needs a lot of energy. A lot of pressure is required for deionisation. Water acidity level increases, as minerals get deionised.
Multistage flash distillation refers to desalination water distilling seawater, by flashing water portions in steams in various stages of concurrent heat exchangers.Advantages - Its Cost efficient , distillation uses waste heat. It has High gain output ratio. Quality of feedwater is less significant, compared to reverse osmosis.
Disadvantages - It has high operating cost in case of waste heat unavailability. High temperature imply high corrosion & scale formation.
To obtain pure lead, lead (II) sulfide is burned in an atmosphere of pure oxygen. The products of the reaction are lead and sulfur trioxide (SO3). Write a balanced chemical equation for this process. How many grams of lead will be produced if 2.54 grams of PbS is burned with 1.88 g of O2? Express your answer to the correct number of significant figures. Be sure to show all steps completed to arrive at the answer. (Hint: be sure to work the problem with both PbS and O2).
Answer: 2.20 g Pb
They gave us the masses of two reactants and asked us to determine the mass of the product. We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 239.27 32.00 207.2
2PbS + 3O₂ ⟶ 2Pb + 2SO₃
m/g: 2.54 1.88
please help- science
1. - new
2. full
3. first quarter
4. last quarter
Answer:
2. Full
Explanation:
A lunar eclipse occurs at a full moon when Earth is directly between the moon and the sun. During a lunar eclipse, Earth blocks sunlight from reaching the moon.
Hope this helps!!
When calcium forms an ion that has the same number of outer electrons as which noble gas?
1. neon
2. helium
3. argon
4. krypton
BRAINLIEST FOR HELP ASAP!!!!
A helium-filled balloon contains 0.16 mol He at 101 kPa and a temperature of 23°C. What is
the volume of the gas in the balloon?
V = 3.9 L
Explanation:
Given:
T = 23°C + 273 = 296K
n = 0.16 mol He
P = 101 kPa = 0.997 atm
R = universal gas constant = 0.08205 L-atm/mol-K
V = ?
Using the ideal gas law,
PV = nRT
V = nRT/P
= (0.16 mil He)(0.08205 L-atm/mol-K)(296K)/(0.997 atm)
= 3.9 L
One method of increasing the chances of particles colliding during a reaction is to...
1)decrease temperature
2) decrease concentration
3)increasing concentration
4)use a catalyst
Answer:
3
Explanation:
Increasing concentration
2+4 help please i will fail 6th grade
Answer:
6
Explanation:
lol
How many grams water will condense when 56,500 joules of energy is removed from steam at its boiling point
Answer:
Start your streak by answering any question. You'll get bonus points from day 2.
What happens to iron when it melts?
O A. It undergoes a chemical change.
O B. It undergoes a physical change.
O c. Its atoms break apart and form new atoms.
O D. Its atoms combine and form new atoms.
Answer:
B. It undergoes a physical change.
Explanation:
Hello there!
In this case, since we know that chemical changes lead to the formation of new atoms and/or compounds due to the bonds rearrangement of the initial substances and the physical changes occur without changing the composition of the initial substances, we can infer that, since melting is a process that changes the phase of matter from solid to liquid without changing the identity of the initial substance, the answer to this question would be B. It undergoes a physical change. because the other options describe chemical changes.
Best regards!
Answer:
B. It undergoes a physical change.
Explanation:
At room temperature, the iron atoms are in an unusual loosely packed open arrangement; as iron is heated past 912 degrees Celsius, the atoms become more closely packed before loosening again at 1,394 degrees Celsius and ultimately melting at 1,538 degrees Celsius.
A balloon is inflated with 1.25 L of helium at a temperature of 298K. What is
the volume of the balloon when the temperature is 310K?
Answer:
What is
the volume of the balloon when the temperature is 310K?
Solid AgCl (Ksp = 1.8 X 10-10) is placed in a beaker of water. After a period of time, the Ag+ concentration is measured and found to be 2.5 X 10-7 M.
a) What is the concentration of Cl-?
b) Has the system reached equilibrium?
c) Will more AgCl dissolve?
Explanation:
a)
[tex]k _{sp} = [Ag {}^{ + } ][Cl {}^{ - } ] \\ but \: [Ag {}^{ + } ] = [Cl {}^{ - } ] \\ k _{sp} = [Ag {}^{ + } ] {}^{2} \\ [Ag {}^{ + } ] = \sqrt{k _{sp}} \\ = \sqrt{1.8 \times {10}^{ - 10} } \\ = 1.34 \times {10}^{ - 5} mol {dm}^{ - 3} [/tex]
b)
It has not reached equilibrium because the silver concentration is not yet equal to the value of Ksp.
c)
Yes it will dissolve in order to establish the equilibrium.
PLEASE HELP REAL ANSWER NO FILE. Part A
Electricity generated from any source comes with its own advantages and
disadvantages. So, no source of energy for generating electricity is perfect. However,
imagine that there is an energy source that perfectly meets the needs of society.
Describe this ideal source of energy. Include relevant factors such as cost, supply, safety,
reliability, and environmental impact
Answer:
Wind energy
Explanation:
An ideal source of energy needs to be reliable, cost effective, safe and must lead to almost zero adverse environmental impact.
Wind energy is energy obtained from air moving at high velocity. This energy is harvested using windmills which convert mechanical energy to electrical energy.
Wind is inexpensive because it occurs naturally. However, a large expanse of land is required in order to mount sufficient number of windmills that will generate enough electrical energy for practical purposes.
This method of electricity generation is safe and does not lead to any environmental hazard unlike the burning of fossil fuels, use of nuclear energy or loss of habitat due to hydroelectric power generation.
PLEASE HELP!! NO LINKS PLEASE REAL ANSWER!!!!!
What will be volume of 20.0 g of CH4 gas at a pressure of 0.950 atm and temperature of 21.0 oc?Question 1 options:
A. 21.8 L
B. 31.8 L
C. 2.27 L
D. 4.27 L
what is the percent composition of calcium fluoride
Answer:
78.07
Explanation:
them seperatly is
Calcium Ca 51.333%
Fluorine F 48.667%
determine the maximum amount of NaN03 that was produced during the experiment. Explain how you determined the amount
Answer:
9 moles of NaNO3 is obtained
Explanation:
The balanced chemical reaction equation for the reaction is;
Al(NO3)3 + 3NaCl-------> 3NaNO3 + AlCl3
Now, we have to determine the limiting reactant. The limiting reactant yields the least amount of NaNO3.
1 mole of Al(NO3)3 yields 3 moles of NaNO3
4 moles of Al(NO3)3 yields 4 * 3/1 = 12 moles of NaNO3
Also,
3 moles of NaCl yields 3 moles of NaNO3
9 moles of NaCl yields 9 * 3/3 = 9 moles of NaNO3
Hence, NaCl is the limiting reactant and 9 moles of NaNO3 is obtained.
9 moles of NaNO₃ is obtained.
Balanced chemical reaction:
[tex]Al(NO_3)_3 + 3NaCl-----> 3NaNO_3 + AlCl_3[/tex]
From the reaction, it is seen that the limiting reactant yields the least amount of NaNO₃.
1 mole of Al(NO₃)₃ yields 3 moles of NaNO₃
4 moles of Al(NO₃)₃ yields 4 * 3/1 = 12 moles of NaNO₃
Also,
3 moles of NaCl yields 3 moles of NaNO₃
9 moles of NaCl yields 9 * 3/3 = 9 moles of NaNO₃
Hence, NaCl is the limiting reactant and 9 moles of NaNO₃ is obtained.
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