Answer:
we will except an increase in the polarity of the system and this will cause the Non-polar spot to be near the solvent front, while the polar spot will run at an approximate speed of 0.5 Rf
Explanation:
when we run a TLC plate in a 50/50 mixture of hexanes and ethyl acetate we will except an increase in the polarity of the system and this will cause the Non-polar spot to be near the solvent front, while the polar spot will run at an approximate speed of 0.5 Rf
The speed of the polar spot depends largely on the level of polarity, an increase in the polarity will see both spots of Neat hexane run when we run a TLC plate in a 50/50 mixture of hexanes and ethyl acetate
7. What must you do before you make a hypothesis?
Answer:
Ask a question?
Explanation:
look at the scientific method uwu
What is the answer? Please
Answer:
true
Explanation:
what is the answer? please
What mass of aluminum has a total nuclear charge of 3.0 C?Aluminum has atomic number 13. Suppose the aluminum is all of the isotope with 14 neutrons.
Answer:
The value is [tex]m = 6.48*10^{-5} \ g [/tex]
Explanation:
From the question we are told that
The total nuclear charge is [tex]Q_t = 3.0 \ C[/tex]
The atomic number is [tex]n = 13[/tex]
The number of neutrons is [tex]n = 14[/tex]
Generally the number of protons is mathematically represented as
[tex]N_p = \frac{Q_t}{p}[/tex]
Here p is the charge on a proton with the value [tex]p = 1.60 *10^{-19} \ C[/tex]
=> [tex]N_p = \frac{3}{p}[/tex]
=> [tex]N_p = \frac{3}{1.60 *10^{-19} }[/tex]
=> [tex]N_p = 1.875*10^19 \ protons [/tex]
Generally the number of atoms present is mathematically represented as
[tex]N_a = \frac{N_p}{n }[/tex]
=> [tex]N_a = \frac{ 1.875*10^19}{13}[/tex]
=> [tex]N_a = 1.44*10^{18} \ atoms [/tex]
Generally the number of moles of atom present is mathematically represented as
[tex]N = \frac{N_a}{A_n }[/tex]
Here [tex]A_n[/tex] is the Avogadro's number with a constant value
[tex]A_n = 6.023*10^{23}[/tex]
So
[tex]N = \frac{1.44*10^{18}}{6.023*10^{23} }[/tex]
=> [tex]N = 2.4*10^{-6} \ mol[/tex]
Generally the total mass is mathematically represented as
[tex]m = N * M[/tex]
Here M is the molar mass of aluminum with
[tex]M = 27 \ g/mol[/tex]
So
[tex]m = 2.4*10^{-6} * 27[/tex]
[tex]m = 2.4*10^{-6} * 27[/tex]
[tex]m = 6.48*10^{-5} \ g [/tex]
The mass of aluminum has a total nuclear charge of 3.0 C is 6.45 * 10⁻⁵ g
Number of protonsNumber of protons = nuclear charge/charge on protonnuclear charge = 3.0 C
mass of proton = 1.60 * 10⁻¹⁹ C
Number of protons = 3.0/1.60 * 10⁻¹⁹ C
Number of protons = 1.875 * 10¹⁹ protons
Number of atomsNumber of atoms = number of protons /atomic numberatomic number = 13
Number of atoms = 1.875 * 10¹⁹/13
Number of atoms = 1.44 * 10¹⁸ atoms
Number of moles of atomsMoles of atoms = number of atoms / 6.02 * 10²³moles of atoms = 1.44 * 10¹⁸/ 6.02 * 10²³
moles of atoms = 2.39 * 10⁻⁶ moles
Mass of aluminummass = number of moles * molar massmolar mass of Aluminum is 27 g
mass of aluminum = 2.39 * 10⁻⁶ * 27
mass of aluminum = 6.45 * 10⁻⁵ g
Therefore, the mass of aluminum has a total nuclear charge of 3.0 C is 6.45 * 10⁻⁵ g
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A diprotic acid, H₂A, has Ka1 = 3.4 × 10⁻⁴ and Ka2 = 6.7 × 10⁻⁹. What is the pH of a 0.18 M solution of H₂A?
Answer:
pH = 2.10
Explanation:
We name an acid as diprotic because it can release two protons:
H₂A + H₂O ⇄ H₃O⁺ + HA⁻ Ka₁
HA⁻ + H₂O ⇄ H₃O⁺ + A⁻² Ka₂
We propose the mass balance:
Analytical concentration = [H₂A] + [HA⁻] + [A⁻²]
As Ka₂ is so small, we avoid the [A⁻²] so:
0.18 M = [H₂A] + [HA⁻]
But we can not avoid the HA⁻, because the Ka₁. Ka₁'s expression is:
Ka₁ = [H₃O⁺] . [HA⁻] / [H₂A]
We propose the charge balance:
[H₃O⁺] = [HA⁻] + [A⁻²] + [OH⁻]
As we did not consider the A⁻², we can miss the term and if
Kw = H⁺ . OH⁻
We replace Kw/H⁺ = OH⁻. So the new equation is:
[H₃O⁺] = [HA⁻] + Kw / [H₃O⁺]
The acid is so concentrated, so we can avoid the term with the Kw, so:
[H₃O⁺] = [HA⁻]
In the mass balance we would have:
0.18 M = [H₂A]
We replace at Ka₁
Ka₁ = [H₃O⁺] . [HA⁻] / [H₂A]
Ka1 . 0.18 / [H₃O⁺] = [HA⁻]
We replace at the charge balance:
[H₃O⁺] = Ka1 . 0.18 / [H₃O⁺]
[H₃O⁺]² = 3.4×10⁻⁴ . 0.18
[H₃O⁺] = √(3.4×10⁻⁴ . 0.18)
[H₃O⁺] = 7.82×10⁻³
- log [H₃O⁺] = pH → - log 7.82×10⁻³
pH = 2.10
Following are the calculation to the pH:
For First ionization:
[tex][H^+] = (K_{a1} \times C)^{\frac{1}{2}}[/tex]
where
C = initial concentration of acid [tex]= 0.18\ M[/tex]
[tex][H^{+}] = (3.4 \times 10^{-4} \times 0.18 \ M)^{\frac{1}{2}}\\[/tex]
[tex][H^{+}] = 0.007\ M[/tex]
For Second ionization:
[tex][H^{+}] = K_{a2} \\\\[/tex]
[tex][ H^{+} ] = 6.7 \times 10^{-9}\ M \\[/tex]
[tex]Total [H^{+}] = 0.007\ M + 6.7 \times 10^{-9}\ M\\\\Total [H^{+}] = 0.007 \ M[/tex]
[tex]pH = -\log[H^+] \\\\pH = -\log(0.007 \ M)\\\\pH = 2.15[/tex]
Therefore, the pH is "2.15".
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Rounding 6.42 g to 2 significant figures
Answer:
6.4
Explanation:
Water that is heated move
PLS HELP !!!
Answer:
it moves faster when heated
Answer:
the answer is faster
Explanation:
why because water moves faster when heated
1)
Which of the following would a chemist be most likely to study?
A what happens when a moving car comes to a stop
B.
what happens when iron rusts in the presence of water
C. what happens when ice melts to form liquid water
D. what happens when light reflects from a shiny surface
Answer:
B. what happens when iron rusts in the presence of water
Explanation:
Chemistry is a branch of science involving the composition and changes of matter. In other words, a chemist, who is a trained specialist in the science of chemistry, seeks to answer questions related to properties of matter.
In this question, a chemist is most likely to study "what happens when iron rusts in the presence of water" because it involves a change in the chemical properties of a substance (iron) i.e. a chemical change. However, what happens when ice melts to liquid water is a physical change.
Which term describes the energy an object has because of its motion?
Answer:
kinetic
Explanation:
What should you do every time you are about to heat glassware on a hot plate?
Select one or more:
Check that there are no cracks in the glassware
Ensure that the glassware is designed for heating
Inspect the hot plate for frayed cords
0 Measure the height and width of the glassware
Answer:
Ensure that the glassware is designed for heating
Check that there are no cracks in the glassware
Inspect the hot plate for frayed cords
Explanation:
All except measuring the height and width of the glassware could cause hazards within the lab.
indigestion tablets neutralise acid in the stomach. what does this tell you about indigestion tablets?
Answer:
It is basic.
Explanation:
Bases can neutralize acids.
What is the volume of a sample of matter with a density of 6 and a mass of 6 cm3?
Answer:
We have the final answer as
1.0 cm³Explanation:
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
mass = 6 g
density = 6 g/cm³
It's volume is
[tex]volume = \frac{6}{6} = 1 \\ [/tex]
We have the final answer as
1.0 cm³Hope this helps you
What determines the shape and function of a protein?
The shape and function of a protein are primarily determined by its three-dimensional structure, which is a result of its primary, secondary, tertiary, and quaternary structures.
Primary Structure: The primary structure of a protein is the linear sequence of amino acids that make up the polypeptide chain. The sequence is dictated by the genetic information encoded in the DNA of the gene that corresponds to the protein. Each amino acid in the sequence is represented by a specific codon in the DNA, and this sequence of amino acids forms the backbone of the protein.
Secondary Structure: The secondary structure refers to the local spatial arrangement of the polypeptide backbone, which is stabilized by hydrogen bonds between amino acids. The two most common secondary structures are alpha-helices and beta-sheets. These structures are important for the stability and folding of the protein.
Tertiary Structure: The tertiary structure is the three-dimensional folding of the entire polypeptide chain, including the secondary structure elements. Various interactions, such as hydrogen bonds, disulfide bridges, ionic interactions, hydrophobic interactions, and van der Waals forces, play a crucial role in stabilizing the tertiary structure. This folding brings distant parts of the polypeptide chain close together, contributing to the unique shape of the protein.
Quaternary Structure: Some proteins are composed of multiple polypeptide subunits, and the way these subunits come together forms the quaternary structure of the protein. The interactions between the individual subunits contribute to the overall structure and function of the complex protein assembly.
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Humans breathe about 500 mL of air per breath and take about 12 breaths per minute during normal activities. If a person is exposed to an atmosphere containing benzene at a concentration of 10 ppm (by volume), how many grams of benzene will be deposited in the lungs during an 8-hour shift if all the benzene that enters remains in the lungs
Answer:
mass of benzene in the lungs = 28.8 g of benzene
Explanation:
Volume of air breathed per hour = 500 mL * 12 * 60 = 360000 ml = 360 Litres of air
In 8 hours, volume of breathed air = 360 L * 8 = 2880 Litres of air
Concentration of benzene in air = 10 ppm
Note: 1 ppm = 1 mg per liter (mg/L)
10 ppm = 10 mg/L
Therefore, mass of benzene in the lungs in an 8-hour shift = 10 mg/L * 2880 L
mass of benzene in the lungs = 28800 mg
Converting to grams = 28800/1000
mass of benzene in the lungs = 28.8 g of benzene
The charge on the cobalt ion in the salt CoO is ________.
Answer:
The charge of cobalt in the salt is + 2.
Explanation:
The charge of the salt = 0 . This is because it is neutral.
Charge of cobalt = ?
Charge of oxygen = -2 (This is a constant value, it is -2 only in peroxides)
Charge of salt = Charge of cobalt + Charge of oxygen
0 = x + (-2)
x = + 2
The charge of cobalt in the salt is + 2.
Which of the following is characteristic of grasslands, but not savannas? a. wide temperature range b. two seasons c. droughts and fires d. wet and dry seasons
Answer:
wide temperature range
Explanation:
Grasslands are ecosystem that covers grass and herbs. It can occur in any type of climates. The rainfall is low in grasslands but it is periodic. The temperature in the summer can exceed 100 degrees Fahrenheit in grasslands.
Savannas is a type of grasslands. It is also known as tropical grasslands. They have average annual temperatures that only vary between 70 and 78 degrees Fahrenheit.
It can be concluded that, out of the given options, that shows the characteristic of grasslands, but not savannas is option (a) " wide temperature range".
Answer: A. wide temperature range
Explanation: Got it correct on the Edgenuity 2020 quiz :)
Zirconium dioxide (ZrO2), sometimes known as zirconia, is a white crystalline oxide of zirconium. It can be used in oxygen sensors and fuel cell membranes because it has the ability to allow oxygen ions to move freely through the crystal structure at high temperatures. The ionic radius of Zr is 0.079 nm, and the ionic radius of Cl is 0.140 nm. What is the coordination number of ZrO2?a. 3b. 6c. 4
Answer:
The coordination number of ZrO₂ = 6
Explanation:
A crystal structure is determined by the ratio of ionic radii of the positive and negative ions present in the crystal.
The ratio of the radii of the positive(cations) and negative(anions) is called the limiting radius ratio and it gives the coordination number of the crystal.
Limiting radius ratio = radius of cation/radius of anion
For ZrO₂:
radius of Zr ion (Zr⁴⁺) = 0.079 nm; radius of O ion (O²⁻) = 0.140 nm
Limiting radius ratio = 0.079 nm/0.140 nm = 0.564
From tables, when the limiting radius ratio value is between 0.414 - 0.732, the coordination number is six and the shape of the crystal is octahedral.
Therefore, the coordination number of ZrO₂ = 6
Which of these statements is supported by the results of Thomson’s experiment? Check all of the boxes that apply.
Atoms are indivisible.
Cathode rays are made up of negatively charged particles.
Atoms contain negatively charged particles.
Answer: Cathode rays are made up of negatively charged particles.
Atoms contain negatively charged particles.
Can you help me answer the question ?
A 60.04 g sample of a compound of carbon, sulfur, hydrogen and oxygen is burned completely. Calculate the empirical formula if 44.8 L of water at STP and 88.0 g of CO2 is formed. In another experiment, a 15.00 g sample of the compound produced 1.00L SO2 at 25.0 oC and 3.05 atm. In a final experiment: 3.57 L of the compound at 2.33 atm and 25 o C weighted 35.0g Find the molecular formula of the compound.
Answer:
Empirical formula: C₂SH₄
Molecular formula: C₄S₂H₈
Explanation:
The empirical formula is the simplest whole ratio of atoms presents in an element.
The compound contains C, S and H, its empirical formula is CₐSₓHₙ. We need to determine a, x and n solving for the moles of each element, thus:
Moles H₂O - moles H-:
PV/RT = n
At STP, P is 1atm, and T is 273.15K:
1atm*44.8L / 0.082atmL/molK*273.15K
moles H₂O = 2 moles water = 4 moles of H
Because 1 moles of water contains 2 moles of H
Moles CO₂ = moles C:
88.0g CO₂ * (1mol / 44g) = 2 moles CO₂ = 2 moles C
The mass of carbon is:
2 moles * (12g/mol) = 24g
Mass of hydrogen:
4 moles * (1g/mol) = 4g
The mass of S is:
60.04g - 24g - 4g = 32.04g = 1 mole of S
Empirical formula is:
C₂SH₄Now, the moles of the compound in the final experiment are:
PV / RT = n
2.33atm*3.57L / 0.082atmL/molK*298.15K = 0.34 moles
-25°C = 298.15K. In gas laws you must use absolute temperature given in Kelvin-
These moles are in 35.0g. The molar mass of the compound is:
35.0g / 0.34 moles = 102.9g/mol
As the empirical formula is C₂SH₄ and weighs 60g/mol. Twice the empirical formula are the molecular formula:
C₄S₂H₈The Molecular formula of the compound: C₄S₂H₈
Empirical formula:It is the simplest whole number ratio of atoms present in a compound.The compound contains C, S and H, its empirical formula is CₐSₓHₙ. We need to determine a, x and n solving for the moles of each element, thus:Moles of H₂O= Moles of H:[tex]n=\frac{PV}{RT}[/tex]
At STP, P is 1atm, and T is 273.15K:
[tex]n= \frac{1atm*44.8L}{0.082atmL/molK*273.15K}[/tex]
Moles H₂O = 2 moles water = 4 moles of H
As, 1 moles of water contains 2 moles of H
Moles of CO₂ = Moles of C:88.0g CO₂ * (1mol / 44g) = 2 moles CO₂ = 2 moles C
We know,
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Mass of carbon is: [tex]2 moles * (12g/mol) = 24g[/tex]
Mass of hydrogen is: [tex]4 moles * (1g/mol) = 4g[/tex]
Mass of sulphur is: [tex]60.04g - 24g - 4g = 32.04g[/tex] = 1 mole of S
The derived Empirical formula will be: C₂SH₄
Now, the moles of the compound in the final experiment are:
[tex]n= \frac{PV}{RT}\\\\n=\frac{2.33atm*3.57L}{0.082atmL/molK*298.15K}\\\\ n= 0.34 moles[/tex]
These moles are in 35.0g. The molar mass of the compound is: [tex]\frac{35.0g}{0.34 moles} =102.9g/mol[/tex]
As the empirical formula is C₂SH₄ and weighs 60g/mol.
The empirical formula is two times the molecular formula: C₄S₂H₈
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A solid keeps its shape due to which of the following factors? (3 points)
а
Space between particles
Attractive forces between particles
b
Ос
The type of element in the solid
Od
The container it is placed in
Answer: Attractive forces between particels
Explanation:
The Avogadro constant is defined as
Answer:
Hope this may help you
5400 L to KL
With work??
Answer:
5.4KL
Explanation:
Divide by 1000
when the temperature of a sample of liquid increases , what else increases ?
Answer:
Its kinetic energy.
Explanation:
In a liquid, the molecules are so close together that there is very little empty space. A liquid also has a definite volume, because molecules in a liquid do not break away from the attractive forces. The molecules can, however, move past one another freely, and so a liquid can flow, can be poured, and assumes the shape of its container.
An increase in the temperature of a liquid causes an increase in the average speed of its molecules. As the temperature of a liquid increases, the molecules move faster thereby increasing the liquid's kinetic energy.
an element has atomic number and mass number 13 and 27 respectively. what are the number of electrons protons and neutrons in one atom of the element
Answer:
the number of electrons is 13 and neutrons is 14
What is the mass of a block that measures 6.7cm x 6.8cm x4.3cm and has a density of 22.29g/cm³
Answer:
4366.8 grams or 4.4 kg
Explanation:
Density = Mass / Volume
Mass = Density x Volume
M = 6.7 x 6.8 x 4.3 x 22.29
M = 4366.8 g
Best Regards!
What is heat?
O Fire
O Hot
O Energy
O Potential
Answer:
Energy
Explanation:
Heat is a form of energy.
Which statement best describes the polarity of SCL4F2?
a. The molecule is always polar.
b. The molecule s always nonpolar.
c. Depending on the arrangement of outer atoms, this molecule could be polar or nonpolar.
Answer: Depending on the arrangement of outer atoms, this molecule could be polar or nonpolar.
Explanation:
Polarity is when the electric charge that is leading to a molecule is being separated.
The polarity of SCL4F2 can either be polar or non polar and this depends on the arrangement of outer atoms. It is the arrangements of these outer atoms that'll help in the determination of its polarity.
The molecule SCl4F2 could be polar or nonpolar depending on the arrangement of outer atoms.
The molecule SCl4F2 could have different arrangements of outer atoms. That means that there are two possible arrangements of the molecule. Depending on which arrangement the outer Cl and F atoms have, the molecule cold be polar or nonpolar.
In the arrangement of SCl4F2 which could be polar is the one in which the dipoles in the molecule do not cancel out. In the other arrangement, the dipoles cancel out and the molecule is nonpolar.
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How many moles are in 34.0 g of dinitrogen oxide?
Answer:
0.773 mole
Explanation:
From the question given above, the following were obtained:
Mass of dinitrogen oxide (N₂O) = 34 g
Mole of N₂O =.?
Next, we shall determine the molar mass of N₂O. This can be obtained as follow:
Molar mass of N₂O = (14 × 2) + 16
= 28 + 16 = 44 g/mol
Finally, we shall determine the number of mole in 34.0 g of dinitrogen oxide (N₂O) as follow:
Mass of dinitrogen oxide (N₂O) = 34 g
Molar mass of N₂O = 44 g/mol
Mole of N₂O =.?
Mole = mass /Molar mass
Mole of N₂O = 34/44
Mole of N₂O = 0.773 mole
Therefore, 0.773 mole is present in 34 g of dinitrogen oxide
Which of the following is a homogenous mixture? a. water b. chicken c. raisin bread d. salad
B and C are ur answers
Suppose you are given samples of pentane, 2,2-dimethylpropane, 2-methylbutane and hexane. how you would go about determining which substance had the highest boiling point.
Answer:
Addiction
Explanation: