Answer: here is your answer
Explanation: You are visiting your Grandmother and notice that she is eating a balanced diet, taking vitamins, getting the proper amount of sleep and is not overweight. Despite her healthy lifestyle, she appears run down and tired. You realize that it's due to her lack of physical activity. Write a convincing letter to your grandma explaining the benefits of participating in regular physical activity.
How many 20 mL extractions of organic solvent are needed to extract at least 99.5% of 50.0 g Compound A from 100 mL of water if K
Answer:
5 extractions to extract at least 99.5% of 50.0 g Compound A from 100 mL of water
Explanation:
If K=10...
Partition coefficient is defined as the ratio of concentrations of a compound A in two inmiscibles solvents:
K = 10 = Conc. Organic solvent / Conc. Water
Usually organic phase over aqueous phase.
In the first 20mL extraction, the organic solvent will extract:
10 = X / 20mL / (50.0g - X) / 100mL
10 = 100X / (1000-20X)
10000 - 200X = 100X
10000 = 300X
X = 33.3g of compound A are extracted in the first extraction
Remember you want to extract 99.5%, that is 50.0g*99.5% = 49.75g
In the aqueous phase remain: 50-33.3g = 16.7g:
Second extraction:
10 = X / 20mL / (16.7g - X) / 100mL
10 = 100X / (334-20X)
3340 - 200X = 100X
3340 = 300X
11.1g are extracted and will remain: 16.7g - 11.1g = 5.6g
Third extraction:
10 = X / 20mL / (5.6g - X) / 100mL
10 = 100X / (112-20X)
1120 - 200X = 100X
1120 = 300X
3.8g are extracted and will remain: 5.6g - 3.8g = 1.8g
Fourth extraction:
10 = X / 20mL / (1.8g - X) / 100mL
10 = 100X / (36-20X)
360 - 200X = 100X
360 = 300X
1.2g are extracted and will remain: 1.8g -1.2g = 0.6g
Fifth extraction:
10 = X / 20mL / (0.6g - X) / 100mL
10 = 100X / (12-20X)
120 - 200X = 100X
120 = 300X
0.4g are extracted. The total extractions gives:
33.3g + 11.1g + 3.8g + 1.2g + 0.4g = 49.8g
That means, you need to do:
5 extractions to extract at least 99.5% of 50.0 g Compound A from 100 mL of waterThe term organic does not mean “natural” true or false
A student was performing a separation of a mixture of organic compounds. The final step of the process involved a filtration of the analyte from an aqueous solution. After drying the filtered solid for a very short period time, they took the melting point of the compound. The measured melting point range of the compound was 106 – 113.8 0C, while the literature melting point of the compound was 122.3 0C. The above scenario is a very common one in organic labs.
1. Do you think their sample was pure?
2. If not, then what do you think could be the source of error.
3. How do you think this error can be minimized?
Answer:
1) No
2) The solvent contaminated the analyte
3) The solvent should be evaporated properly before washing and drying the analyte
Explanation:
During separation of organic compounds, solvents are used. These solvents are able to contaminate the analyte and lead to a large difference in melting point of solids obtained.
However, the error can be minimized by evaporating the solvent before washing, drying and melting point determination of the solid.
20
How do you determine the number of barium atoms in the formula below?
4Ba(OH)2
F
# of Ba atoms = coefficient 4 + subscript 1 = 5
G
# of Ba atoms = coefficient 4 X subscript 1 = 4
H
# of Ba atoms = subscript 4 X coefficient 2 = 6
# of Ba atoms coefficient 1 + subscript 1 = 2
J
Answer:
G is correct option:
# of Ba atoms = coefficient 4 × subscript 1= 4
Explanation:
Formula:
4Ba(OH)₂
G is correct option:
# of Ba atoms = coefficient 4 × subscript 1= 4
Because there are only 4 atoms of Ba in given formula.
Ba(OH)₂ contain one atom of Ba while in question there are 4 moles of Ba(OH)₂ present thus total 4×1 = 4 atoms of Ba present.
Other options are incorrect. Because,
F:
# of Ba atoms = coefficient 4 + subscript 1 = 5
This shows given formula contain 5 Ba atoms. So it is incorrect.
H:
# of Ba atoms = subscript 4 × coefficient 2 = 6
This shows that subscript is 4 which is incorrect because coefficient is 4 and subscript is 1.
j:
# of Ba atoms = subscript 1 + coefficient 1 = 2
This option shows that subscript is one which is correct but coefficient is incorrect. The coefficient of Ba is 4 and coefficient is always multiply with subscript not added. So this option is also incorrect.
Be sure to answer all parts.
Write a balanced equation for each reaction. Do not include states of matter to your equation.
H2 + O2 H20
Answer:
2H₂ + O₂ → 2H₂O
Explanation:
Chemical equation:
H₂ + O₂ → H₂O
Balance chemical equation:
2H₂ + O₂ → 2H₂O
Step 1:
H₂ + O₂ → H₂O
Left hand side Right hand side
H = 2 H = 2
O = 2 O = 1
Step 2:
H₂ + O₂ → 2H₂O
Left hand side Right hand side
H = 2 H = 4
O = 2 O = 2
Step 3:
2H₂ + O₂ → 2H₂O
Left hand side Right hand side
H = 4 H = 4
O = 2 O = 2
In chemistry, one often uses a unit of charge known as the Faraday, F, which has the magnitude of the charge of 1 mole of electrons. How many faradays of charge does that correspond to
Answer:
1 Faraday
Explanation:
This question seeks to test proper understanding of Faraday's second law of electrolysis which states when the same quantity electricity passes through a solution of different electrolytes, the mass of the substance deposited is directly proportional to there chemical equivalence.
This law hints at the charges of ions being the chemical equivalence and also been represented as the unit for the quantity of electricity in faraday, F. Hence, a metal with the charge of 1+ can be displaced by 1F (which is equal to 96, 500 coloumbs). This charge also represents one molecule of electron, thus 1 faraday corresponds to one mole of electrons.
NOTE: It should be noted that a metal with the charge of 2+ can be displaced by 2F and so on.
A sample of an unknown gas weighs 0.419 grams and produced 5.00L of gas at 1.00atm (unknown gas only) and 298.15K, what is the molar mass (g/mole) of this unknown gas
Answer:
molar mass of unknown gas = 1.987 g/mol
Explanation:
First, the number of moles of the unknown gas is found
Using the ideal gas equation: PV = nRT
P = 1.00 atm, V = 5.00 L, T = 298.15 K, R = 0.082 L.atm.mol⁻¹K⁻¹
n = PV/RT
n = (1.00 atm * 5.00 L)/(298.15 K *0.082 L.atm.mol⁻¹K⁻¹)
n = 0.2109 moles
Molar mass = mass/ number of moles
molar mass = 0.419 g/ 0.2109 mols
molar mass of unknown gas = 1.987 g/mol
The molar mass of unknown gas by using ideal gas equation = 1.987 g/mol.
Ideal gas equationThis equation gives the relation between pressure, volume, temperature as given below:
[tex]PV = nRT[/tex]
P = 1.00 atm, V = 5.00 L, T = 298.15 K, R = 0.082 L.atm.mol⁻¹K⁻¹
Substitute the above values in the above equation as follows:
n = (1.00 atm * 5.00 L)/(298.15 K *0.082 L.atm.mol⁻¹K⁻¹)
n = 0.2109 moles
Formula for molar mass[tex]Molar mass = mass/ number of moles[/tex]
Calculate molar mass by using the above equation,
molar mass = 0.419 g/ 0.2109 moles
The molar mass of unknown gas = 1.987 g/mol
Find more information about ideal gas equation here,
brainly.com/question/4147359
A baseball strikes the roof of a car and dents it. The paint on the roof begins to crack and chip, exposing the metal. The exposed metal on the roof rusts, eventually causing a small hole in the roof. 17. Which event is a chemical change? The baseball strikes the roof The roof of the car dents The paint cracks and chips The exposed metal rusts
Answer:
The exposed metal rusts is an example of a chemical change because rust is an example of a chemical change in objects for example bicycles, scooters, etc.
HELPP GIVING AWAY 30 POINTS!!!!!
Determine Your family wants to use
renewable energy to heat your home. Which
renewable energy resource is best suited to
your area? Explain your answer.
Answer:
wood
Explanation:
i can take the seds from the trees to row new trees and still use the wood without causing deforestation
Two students apply force to a box at rest on the floor.
Left
Right
40 Newtons
30 Newtons
What is the total amount of force in Newtons acting on the box and in which direction?
10 N Left
10 N Right
• 70 N Left
70 N Right
Answer:
10 N Left
Explanation:
Given parameters;
Forces acting on the box
Left force = 40N
Right force = 30N
Unknown:
Net force on the box and the direction = ?
Solution:
Force is a pull or push on a body;
← BODY →
40N 30N
The forces acting on the body are in the opposite directions, the greater force will determine the direction of pull.
Net force = Left force - Right force = 40 - 30 = 10N
The force will be directed left with a net value of 10N
Which of the following is NOT a strong electrolyte?
:
Answers:
Na2SO4
KI
CaCl2
LiOH
C6H1206
Answer:
C6H1206
Explanation:
C6H12O6 is a monomer of carbohydrates also known as glucose, so it is not an electrolyte at all.
Please answer !! For chemistry
Answer:
a. is the correct answer
Explanation:
Which of the following evidence supports the theory of plate tectonics
Answer:
seafloor spreading
Explanation:
i took the test
Four grams of hydrogen react completely with 32 grams of oxygen. Based on the law of conservation of mass how many grams of water will be produced
Se producirán 36 gramos de agua
Explicación: Ya que en una reacción química no puede descubrir ningún cambio en masa total de las sustancias que en ella intervienen, pues en una reacción química ni se gana ni se pierde masa.
What is the correct 1 letter code for the amino acid sequence Glutamic Acid-Histadine-Tyrosine Select one: a. E-H-Y b. G-H-T c. Q-H-T d. E-H-T
Answer:
a. E-H-Y
Explanation:
A group of three nucleotides is called a codon that codes for a specific amino acid in the protein. There are 20 essential amino acids present in human body and are required in the diet.
Each amino acid is given a one-letter code that makes the study of amino acid sequences easy. One letter code for the given amino acid sequence Glutamic Acid-Histidine-Tyrosine is E-H-Y in which E is code for Glutamic Acid, H is a code for Histidine, and Y is a code for Tyrosine.
Hence, the correct answer is "a. E-H-Y".
CHEMISTRY!! 50 POINTS!
There are 5.5 L of a gas present at -38.0 C. What is the temperature if the volume of the gas has changed to 1.30 L?
Answer:
The answer to this question is 33.8
What does chemical equations and chemical formulas have in common?
Answer:
Chemical symbols refer to chemical elements only. They do not necessarily refer to atoms of that element, but also to ions.
Explanation:
Question 11
4 pts
Using the formula 2H202 --> 2H2O + O2, if 7.30 moles of peroxide are
decomposed, how many moles of oxygen will be formed?
Answer:
3.65 mol O₂
Explanation:
Step 1: RxN
2H₂O₂ → 2H₂O + O₂
Step 2: Define
Given - 7.30 mol H₂O₂
Solve - x mol O₂
Step 3: Stoichiometry
[tex]7.30 \hspace{3} mol \hspace{3} H_2O_2(\frac{1 \hspace{3} mol \hspace{3} O_2}{2 \hspace{3} mol \hspace{3} H_2O_2} )[/tex] = 3.65 mol O₂
What is the percent error for the experiment if the actual density is
2.49g/mL but the experimental value is 1.47 g/mL?
Answer:
The answer is 40.96%Explanation:
The percentage error of a certain measurement can be found by using the formula
[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\ [/tex]
From the question
actual density = 2.49g/mL
error = 2.49 - 1.47 = 1.02
We have
[tex]p(\%) = \frac{1.02}{2.49} \times 100 \\ = 40.96385542...[/tex]
We have the final answer as
40.96 %Hope this helps you
Plz answer me will mark as brainliest
Explanation:
Valves
Blood capillaries
Which statement gives an advantage of multicellular organisms?
A. Cells are able to provide support
B. They can reproduce quickly
C. Their size allows them to maintain structure easily
D. They need small amounts of energy
Answer:
A. Cells are able to provide support
A species that has 13 protons and 10 electrons will be_____
Answer: Aluminum
Explanation:
Al3+ indicates an ion of aluminum having a charge of + 3. I.e., since an aluminum atom normally has 13 protons and 13 electrons, this ion has 10 electrons (-10 charge) and 13 protons (+ 13 charge) giving it a charge of + 3 (-10 + 13 = +3).
Answer:
Explanation:
Al3+ indicates an ion of aluminum having a charge of + 3. I.e., since an aluminum atom normally has 13 protons and 13 electrons, this ion has 10 electrons (-10 charge) and 13 protons (+ 13 charge) giving it a charge of + 3 (-10 + 13 = +3).
ccto.
If 5.00g of iron metal is reacted with 0.950g of Cl2 gas, how many grams of ferric chloride (FeCl3) will form?
Answer:
1.45g of FeCl3
Explanation:
The equation of the reaction is given as;
2Fe + 3Cl2 --> 2FeCl3
2 mol of Fe reracts with 3 mol of Cl2 to form 2 mol of FeCl3
Upon converting to mass using;
Mass = Number of moles * Molar mass
( 2 * 55.85 = 111.7g ) of Fe reacts with ( 3 * 71 = 213g ) of Cl2 to form ( 2 * 162.2 = 324.4g) of FeCl3
Cl2 is the limiting reactant as it determines how much of FeCl3 is formed
213g of Cl2 = 324.4g of FeCl3
0.950g of Cl2 = x
x = (0.950 * 324.4 ) / 213
x = 1.45g of FeCl3
which one of these best defines climate
please help i will mark brainlest answer if correct asap
Answer:
Long term condition of the atmosphere
Explanation:
I think this is right.
I hope this helps! (✿◕‿◕✿)
HELPPPPP
Identify whether each of the following changes is a physical change or a chemical change. Write “P” on the line for a physical change and a “C” for a chemical change.
22. Water boiling ______23. Iron rusting ______24. Butter melting _____25. Wood rotting ______
26.Alcohol evaporating _____27.Glass breaking ______28.Mowing the lawn ______29.Baking a cake ______
Answer:
22 is P
23 is C
24 is P
25 is C
26 is P
27 is P
28 is P
29 is C because youre using thermal heat and you cannot return to raw batter
If the density of aluminum is 2.7g/ml, what is the volume of 12.0g?
Answer:
The answer is 4.44 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\ [/tex]
From the question we have
[tex]volume = \frac{12}{2.7} \\ = 4.4444444....[/tex]
We have the final answer as
4.44 mLHope this helps you
Based on the visible cell structures, which of the following statements is true?
All of the cells are plant cells.
All of the cells have chloroplasts.
All of the cells are animal cells.
All of the cells have a nucleus.
What is the final concentration if water is added to 0.25 L of a 8M NaOH solution to make 4.0 L of a diluted NaOH solution?
.25 M NaOH solution
1 M NaOH solution
.5 M NaOH solution
Answer:
0.5 M NaOH solution
Explanation:
Initially, we have 0.25L or 250 mL of 8M NaOH solution
Which means that 1L of this solution would have 8 moles of NaOH
Moles present in 250 mL of solution:
Molarity * Volume( in L)
8 * 0.25 = 2 moles
There is 2 moles of NaOH in 0.25 L of the provided NaOH solution
More water is going to be added to this solution but the number of moles of NaOH will remain the same
now that the solution has a volume of 4L after adding the additional water, we have a 4L solution which contains 2 moles of NaOH
Molarity of the new solution:
Molarity = Number of moles in solution / Volume of solution
Molarity = 2 / 4
Molarity = 0.5 M
In the combustion of hydrogen gas, hydrogen reacts with oxygen from the air to form water vapor. hydrogen+oxygen⟶water If you burn 58.9 g of hydrogen and produce 526 g of water, how much oxygen reacted?
Answer:
[tex]m_{O_2}=467gO_2[/tex]
Explanation:
Hello.
In this case, for the reaction:
[tex]2H_2+O_2\rightarrow 2H_2O[/tex]
The correct way to compute the oxygen that reacted is by considering the mass of hydrogen, 58.9 g, its molar mass, 2.02 g/mol, the 2:1 mole ratio between hydrogen and oxygen and the atomic mass of that gaseous oxygen 32.00 g/mol; therefore we use the following stoichiometric procedure:
[tex]m_{O_2}=58.9gH_2*\frac{1molH_2}{2.02gH_2}*\frac{1molO_2}{2molH_2} *\frac{32.00gO_2}{1molO_2} \\\\m_{O_2}=467gO_2[/tex]
The same result could have been obtained by using the mass of water since the law of conservation of mass is obeyed here.
Best regards!
A scientist discovers remnants of an organism on a slide under his microscope. He can only identify a few components: a large vacuole, ridged cell wall, and a chloroplast. Was the organism prokaryotic or eukaryotic? How do you know?
Answer:
Eukaryotic (a plant cell)
Explanation:
The presence of a chloroplast indicates that the cell has membrane-bound organelles. This is not a feature of prokaryotic cells - only eukaryotic cells. Therefore, the cell is eukaryotic. The presence of a large vacuole, chloroplast, and rigid cell wall suggests its a plant cell as plant cells are the only eukaryotes with these features.