Explanation:
Chemistry is overall a very interesting subject and it really depends on what you personally consider enjoyable. I love chemistry and I think that grade 11 chemistry is very easy. It's mostly based on balancing chemical equation, molar mass calculations and more. But it's a great course to take based on my experience.
Suppose that you must go into court and testify as to the level of X in the river water. Your lawyer is concerned that your analytical results are lower than they should be because you cannot extract with benzene (distribution Ratio K=4) all of X from your samples. Assume the concentration of X in the 1.00 L river water sample is 1.06 x 10-4 M.
a. How many extracts would be required to remove all but 1000 molecules of X from the sample with repeated 10.00 mL portions of extract?
b. How many extractions are required for a 99.99% chance of extraction of the last molecule remaining (0.01% chance of a single molecule left behind)
Answer:
The appropriate solution is:
(a) n ≈ 900
(b) n ≈ 1165
Explanation:
According to the question,
(a)
The final number of molecules throughout water will be:
= [tex](\frac{1000}{1000}\times 4\times 10 )^n[/tex]
where, n = number of extractions
Now,
The initial number of molecules will be:
= [tex]1.06\times 10^{-4}\times 6.023\times 10^{23}[/tex]
= [tex]6.387\times 10^{19}[/tex]
Final number of molecule,
⇒ [tex]1.566\times 10^{-16}=(\frac{1000}{1040} )^n[/tex]
[tex]n \approx 900[/tex]
(b)
Final molecules of X = left (0.01%)
hence,
⇒ [tex]initial = 6.384\times 10^{19}[/tex]
[tex]\frac{1}{6.384\times 10^{19}} =(\frac{1000}{1040} )^2[/tex]
[tex]n \approx 1165[/tex]
- Standard state refers to
a) 1 atm and 25°C
b) 1 atm and 100°C
c) 1 atm and gaseous reactants
d) None of these
Answer: The standard state refers to 1 atm and [tex]25^{o}C[/tex].
Explanation:
It is known that a chemical/substance can either be present in a solid, liquid or gaseous state.
So, when the phase of a substance like solid, liquid or gas is present at 1 atmosphere pressure and at a temperature of [tex]25^{o}C[/tex] then it known as standard state of substance.
Thus, we can conclude that standard state refers to 1 atm and [tex]25^{o}C[/tex].
Determine the number of moles in 1.5 x 10^25
atoms of iron.
How many liters of chlorine are needed to produce 5.64 moles of aluminum chloride? Need help ASAP
Answer:
190 L
Explanation:
Given that:
Number of moles = mass/molar mass
number of moles = 5.64
molar mass of aluminum chloride = 133.34 g/mol
∴
The balanced equation is:
2 Al + 3 Cl2 --> 2AlCl3.
From above reaction:
5.64 mole of AlCl3 reacts with 3 mole Cl2 to give 2 mole AlCl3
i.e
[tex](5.64 \ mole \ AlCl3) \times (3 \ mole \ Cl2 \ / \ 2 \ mole \ AlCl3)[/tex]
= 8.46 mole Cl2 gas.
At Standard temperature and pressure:
= (22.4 L/1 mole gas) * (8.46 mole Cl2)
= 190 L chlorine gas
A sample was then prepared containing 14.00 mL of coffee and 8.00 mL of 4.80 ppm Li , and diluted to a 50.00 mL total volume. The ratio of the internal standard signal to the analyte signal in the unknown sample was found to be 0.840/1.000 (Li signal/Na signal). Determine the unknown concentration of Na in the coffee sample.
Answer:
The right answer is "[tex][Na^+]=5.57 \ ppm[/tex]".
Explanation:
The given values are:
[tex]\frac{A_s}{A_{coffee}} =\frac{0.840}{1.000}[/tex]
According to the question,
The concentration of standard will be:
= [tex]\frac{7.80}{50.00}\times 4.80[/tex]
= [tex]0.156\times 4.80[/tex]
= [tex]0.748 \ ppm[/tex]
Coffee after dilution,
⇒ [tex]\frac{A_{coffee}}{C_{coffee}} =F\times \frac{A_s}{C_s}[/tex]
or,
⇒ [tex]C_{coffee}=\frac{A_{coffee}}{A_s}\times \frac{C_s}{F}[/tex]
On substituting the values, we get
⇒ [tex]=\frac{1.000}{0.840}\times \frac{0.748}{1.68}[/tex]
⇒ [tex]=1.191\times 1.3104[/tex]
⇒ [tex]=1.561 \ ppm[/tex]
hence,
In unknown sample, the concentration of coffee will be:
= [tex]1.561\times \frac{50}{14}[/tex]
= [tex]\frac{78.05}{14}[/tex]
= [tex]5.57 \ ppm[/tex]
Calculate the concentration of NO2NO2 in an equilibrium mixture given that the concentration of N2O4=0.200MN2O4=0.200M and Keq=67.3Keq=67.3 for the reaction: 2NO2(g)⇌N2O4(g)2NO2(g)⇌N2O4(g). Calculate the concentration of in an equilibrium mixture given that the concentration of and for the reaction: . 18.3 M 0.00297 M 337 M 0.0545 M none of the above
Answer: The concentration of [tex]NO_{2}[/tex] in the given equilibrium mixture is 0.0545 M.
Explanation:
The ratio of concentration of products and reactants raised to the power of their coefficients is called equilibrium constant. The symbol used to denote equilibrium constant is [tex]K_{eq}[/tex].
As the given reaction equation is as follows.
[tex]2NO_{2}(g) \rightleftharpoons N_{2}O_{4}(g)[/tex]
The expression for equilibrium constant of this reaction is as follows.
[tex]K_{eq} = \frac{[N_{2}O_{4}]}{[NO_{2}]^{2}}[/tex]
Now, substitute the given values into above formula as follows.
[tex]K_{eq} = \frac{[N_{2}O_{4}]}{[NO_{2}]^{2}}\\67.3 = \frac{(0.2)}{[NO_{2}]^{2}}\\So, [NO] = \sqrt{\frac{0.2}{67.3}}\\= 0.0545 M[/tex]
Thus, we can conclude that the concentration of [tex]NO_{2}[/tex] in the given equilibrium mixture is 0.0545 M.
Convert 61 μg of aluminum phosphate to grams. (Hint: 1 μg = 1 x 10-6 g, so multiply 61 by 1 x 10-6)
Answer: 61 μg of aluminum phosphate in grams is equal to [tex]61 \times 10^{-6} g[/tex].
Explanation:
According to standard conversion of units, 1 microgram [tex](\mu g)[/tex] is equal to [tex]1 \times 10^{-6}[/tex] g.
Therefore, [tex]61 \mu g[/tex] is converted into grams as follows.
[tex]1 \mu g = 10^{-6} g\\61 \mu g = 61 \mu g \times \frac{10^{-6}}{1 g}\\= 61 \times 10^{-6} g[/tex]
Thus, we can conclude that 61 μg of aluminum phosphate in grams is equal to [tex]61 \times 10^{-6} g[/tex].
How do scientists determine the names for so many different living things
Answer:
Taxonomy
Explanation:
Select the correct answer.
Your friend Keith has been in a dating relationship for six months. His personality has changed in these months. He looks unhappy and rarely smiles. He avoids the company of friends. On the rare occasions you have seen him, his face appears bruised. You suspect that Keith may be in an abusive relationship. What should you do in this case?
A.
avoid talking to Keith
B.
confront his dating partner
C.
encourage Keith to speak up and report abuse
D.
advise him to tolerate the abuse, as difficulties are a part of life
If 348 grams of Mg(OH)2 reacts with excess HCl (this is CL chlorine, not C and I), how many moles of MgCl2 (this is CL chlorine, not C and I) are produced?
Answer:
moles MgCl₂ = 5.97 moles
Explanation:
First, let0s write the overall reaction that is taking place here:
Mg(OH)₂ + HCl ----------> MgCl₂ + H₂O
Now, we need to balance this reaction:
Mg(OH)₂ + 2HCl ----------> MgCl₂ + 2H₂O
Now, the exercise already stated that the HCl is in excess, so we can assume the magnesium hydroxide is the limiting reactant. If this is true, then, to get the moles of MgCl₂ produced, all we need to do is calculate the moles of Mg(OH)₂ that reacted, using the following expression:
moles = mass / MM
The atomic weights for Mg, O and H are:
Mg: 24.305 g/mol; H: 1 g/mol; O = 15.999 g/mol
Let's determine the molar mass of Mg(OH)₂:
MM = 24.305 + (2 * 15.999) + (2 * 1) = 58.303 g/mol
Now, let's determine the moles:
moles = 348 g / 58.303 g/mol = 5.97 moles of Mg(OH)₂
As we can see in the overall reaction, there is a mole ration between Mg(OH)₂ and MgCl₂ of 1:1, that's why we can conclude that the moles of Mg(OH)₂ would be the same moles of MgCl₂:
moles Mg(OH)₂ = moles MgCl₂ = 5.97 molesHope this helps
Ito ang web browser na kapalit ng Internet Explorer! plsssss help naman ako epp po ito hindi ko po alam
Answer:
p o e t i c o
Explanation:
no lo entenderias
How many moles are in 153 grams of O2?
Answer:
4.78 mol O2
Explanation:
Grams --> moles
Grams/molar mass = moles
153 g O2 / 32 g/mol O2 = 4.78125 (significant figures so round it up; the grams has 3 significant figures, so round it up) 4.78 mol O2
If a 50.0 g piece of glass is heated from 20.0°C to 40.0°C, how many joules of heat are added? The specific heat of glass is 0.50 J/g°C.
Answer:
500J (joules)
Explanation:
since heat is is the product of mass, change in temperature, and specific heat, the solution can be found from the equation q = mcΔt, heat is 50 * .5 * 20 = 500J
What is my formula? Silver l acetate
Answer:
Ag(I)C2H3O2 ....................
Silver only has a single valence value (+1) so you really don't need to put the (I) in the chemical formula.
1 point
To help you with estimating, the individual answers to A, B, C should all
have zero in the one's place. Add those answers up to get the numerical
code. Input that code to move on.*
A) 56 g NH3 can be dissolved in 100 g of water at °C
B) At 50°C, 166 g of KNO, can be dissolved in g of water to make a saturated
solution
C) At 76°C, KCI and HCI have the same solubility. What mass of each could be dissolved in
80 g of water?
Your answer
This is a required question
Back
Next
Answer:ee
Explanation:
How does an ecosystem benefit when leaves fall from a tree and decompose on the soil?
A. Nutrients are released into the soil.
B.Soil erosion decreases
C.Carbon dioxide is absorbed by the soil.
D.Soil temperature decreases.
When leaves fall from a tree and decompose on the soil it benefits the ecosystem as nutrients are released into the soil.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
Learn more about ecosystem,here:
https://brainly.com/question/1673533
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An increase in temperature will cause an increase in diffusion rate because Multiple Choice hot molecules get smaller and therefore diffuse faster. the frequency and force of molecular collisions decreases. hot water changes to a solid, so diffusion is easier. hot water is thinner than cold water. the frequency and force of molecular collisions increases.
Answer:
hot water is thinner than cold water.
Explanation:
The rate of diffusion of a substance has a lot to do with the temperature of a body.
Let us take water for instance, cold water has a greater density than hot water. As a result of this, the molecules in cold water are slower when in motion and more sluggish.
On the other hand, the molecules of hot water are quite faster since hot water has a lower density(thinner than cold water).
Thus, an increase in temperature will cause an increase in diffusion rate because hot water is thinner than cold water.
Which example is the site of oxidation when the dry cell is operating?
solid zinc layer
cardboard separator
graphite rod
paste
A dry cell is one type of electric battery which is generally used for the home and portable electronic devices. A battery is a device which consists of one or more electrochemical cells. The site of oxidation occurs in solid zinc layer. The correct option is A.
What is a dry cell?A dry cell is defined as an electrochemical cell which consists of low moisture immobilized electrolytes in the form of a paste which restricts it from flowing. It is developed by the German scientist Carl Gassner which converts chemical energy into electrical energy.
A dry cell consists of a metal container in which a low moisture electrolyte paste covers the graphite rod or a metal electrode. Generally, the metal container will be zinc whose base perform as the negative electrode (anode).
For a dry cell battery to operate, oxidation will occur from the zinc anode and reduction will take place in the cathode.
Thus the correct option is A.
To know more about dry cell, visit;
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who am I? my number name has the same number of letters as me. I am number _____
Answer:
four
is the answer
THIS IS EASYA scientist wants to investigate several problems. In which of the following situations is using a simulation LEAST suitable for solving a problem?
a. When a scientific study requires performing a large number of trials that need to be conducted very quickly
b. When the solution to the problem requires real-world data inputs that are continually measured at regular intervals.
c. When performing an experiment that would be too costly or dangerous to conduct in the real world
d. When it is considered acceptable to make simplifying assumptions when modeling a real-world object or phenomenon
Answer:
A
Explanation:
got from another website
The simulation which is least suitable to scientists for solving a problem is when performing an experiment that would be too costly or dangerous to conduct in the real world.
What is scientific approach?Scientific approach is an empirical method of acquiring knowledge and result. This method involved the careful observation of the problem, applying skepticism about the problem and giving cognitive assumptions also.
If a scientist wants to investigate several problems, then they will perform a large no. of trials at regular intervals to get the required result. But if performing of any experiment is dangerous to conduct in the real world then scientists will ignore to solve that problem.
Hence, option (C) is correct.
To know more about scientific approach, visit the below ink:
https://brainly.com/question/497944
Use the nutrition label to answer the following questions.
16.How much energy is contained in
the six-cookie serving size
recommended on the label?
17.How much energy in joules is provided by eating
six cookies? (1 cal = 4.184 J; ALSO: 1 Calorie = 1
kilocalorie)
Answer:
six cookies?(1 cal _4.184 j; ALSO: 1 Calorie -1 kilocalorie)
What is the H+ concentration of a substance with a pH of 5?
Answer:
- log{H+ }= - log {5}= -0.6990
How many atoms are there in 24 moles of Fe?
Answer: There are [tex]145 \times 10^{23}[/tex] atoms in 24 moles of Fe.
Explanation:
According to the mole concept, 1 mole of a substance contains [tex]6.022 \times 10^{23}[/tex] atoms.
Therefore, atoms present in 24 moles of Fe are calculated as follows.
[tex]24 mol \times 6.022 \times 10^{23} atoms/mol\\= 144.52 \times 10^{23} atoms\\or, 145 \times 10^{23} atoms[/tex]
Thus, we can conclude that there are [tex]145 \times 10^{23}[/tex] atoms in 24 moles of Fe.
i think its D but i not sure so can yall pls help me
Answer:
I'm not really sure but I thinks its
A:veuns
what it meant by executive mention the function of Executive
[tex]\huge{\textbf{\textsf{{\color{pink}{An}}{\red{sw}}{\orange{er}} {\color{yellow}{:⌐■-■}}}}}[/tex]
Definition:-
The organ of government that primarily looks after the function of implementation and administration is called the executive.
Function:-
Executive is the branch of government responsible for the implementation of laws and policies adopted by the legislature.
ThanksHope it helps.Which of the following lists contain ONLY metals?
Answer:
I'd there and pictures?? can put the list
How do new traits enter a population?
Can someone please help me
Plants!
No doubt the answer is plants they are one maintaining the temperature, responsible for rains too...
IT due tomorrow Giving Brianliest!!!!!
This is not a eassy!!!!!
The ΔHfus for ethanol is 4.60 kJ/mol. If it takes 7500.0 Joules of energy to melt a sample of ethanol, how many grams of ethanol are in the sample? The chemical formula for ethanol is C2H5OH.
Answer:
Explanation: