Answer:
1) 0.1077 moles
2) 137043.2 moles
3) 180.186 grams
4) 6.53×10²² molecules or formula units
5) 1.505×10²³ ions
6) 90.626 grams
7) 0.555 moles
Explanation:
1) The number of moles, n = Mass of the substance/(Molar mass of the substance)
The molar weight of PO₄⁻³ is 94.971 g/mol
The number of moles in 10.23 g of PO₄⁻³ is n =10.23/94.971 = 0.1077 moles
The number of moles in 10.23 g of PO₄⁻³ = 0.1077 moles
2) The number of molecules of Na₂CO₃ in one mole of Na₂CO₃ is given by the Avogadro's number, [tex]N_A[/tex] = 6.02 × 10²³ molecules
Therefore, the number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ is found by determining how many Avogadro's number of molecules are in 8.25 × 10²⁸ molecules of Na₂CO₃ as follows;
The number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ = (8.25 × 10²⁸)/(6.02 × 10²³) = 137043.2 moles
The number of moles in 8.25 × 10²⁸ molecules of Na₂CO₃ = 137043.2 moles
3) The molar mass of CH₂O = 30.031 g/mol
Therefore, the mass of 6 of CH₂O = 6 moles × 30.031 g/mol = 180.186 grams
The mass of 6 of CH₂O = 180.186 grams
4) The molar mass of NaCl = 58.44 g/mol
The number of moles of NaCl in 6.34 g of NaCl 6.34/58.44 = 0.1085 moles
1 formula unit of NaCl = 1 molecule of NaCl
The number of molecules in one mole of a substance = [tex]N_A[/tex] = 6.02 × 10²³
Therefore, the number of molecules in 0.1085 moles of NaCl = 6.02 × 10^(23) × 0.1085 = 6.53×10²² molecules or formula units
5) The number of ions per mole of any substance is give by Avogadro's number, [tex]N_A[/tex] = 6.02 × 10²³ ions,
The number of ions in 0.25 moles of Cu⁺² = 0.25×6.02 × 10²³ ions = 1.505×10²³ ions
The number of ions in 0.25 moles of Cu⁺² = 1.505×10²³ ions
6) The molar mass of CH₄ = 16.04 g/mol
The number of moles, n, in 3.4×10²⁴ = 3.4×10^(24)/(6.02×10^(23)) = 5.65 moles 5.65*16.04
The mass of 5.65 moles of CH₄ = 5.65 moles × 16.04 g/mol = 90.626 grams
The mass of 3.4×10²⁴ molecules of CH₄ = 90.626 grams
7) The density of water = 1 g/mL
The volume of the water 10 mL
The mass of the water = Volume × Density = 10 mL × 1 g/mL= 10 grams
The molar mass of water = 18.015 g/mol
The number of moles of water in 10 g of water = mass/(Molar mass) = 10/18.015 = 0.555 moles.
The mass number of a chromium atom is 52 and it has 24 protons. How many neutrons does this atom have? 24 28 76 80
The number of protons and neutrons together makes the total atomic mass of the element. The atom of chromium has 28 neutrons. Thus, option b is correct.
What is an atomic mass?An atomic mass is the property of an element that defines the number of protons and neutrons of the atom placed in a periodic table. The atomic mass is represented at the lower half of the atomic symbol.
The atomic mass is the sum of the neutrons and the protons that are held together in the nucleus of the atom as a concentrated mass. The atomic number is given as,
Atomic number = number of protons + number of neutrons
Given,
The atomic mass of chromium = 52
Number of protons = 24
Substituting values above:
52 = 24 + number of neutrons
number of neutrons = 52-24
= 28
Therefore, the number of neutrons of a chromium atom is 28.
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Answer: option b, 28
which one of the following electronic configuration represents the element that forms simple ion with a charge of-3? (a)1s^2,2s^2,2p^6,3s^2,3p^1 (b)1s^2,2s^2,2p^6,3s^2,3p^3 (c)1s^2,2s^2,2p^6,3s^2,3p^6,3d^1,4s^2 (d)1s^2,2s^2,2p^6,3s^2,3p^6
Answer:
(b)
Explanation:
The 3s^2, 3p^6 orbitals form -3 charge.
This is the element phosphorous and an example of a -3 ion is in aluminium phosphide, AlP3.
The electronic configuration which represents the element forming a simple ion having with a charge of -3 is; 1s², 2s², 2p⁶, 3s², 3p³. Option B is correct.
In this electronic configuration, the element has a total of 16 electrons. To form a simple ion with a charge of -3, the element needs to gain three electrons. This is achieved by adding three extra electrons to the existing configuration.
When the element gains three electrons, the electron configuration becomes:
1s², 2s², 2p⁶, 3s², 3p⁶
This configuration represents the stable octet configuration, where the element has a complete outer shell with eight electrons. Since the charge is -3, it means the element has gained three extra electrons to achieve a stable configuration.
Therefore, the correct electronic configuration representing the element that forms a simple ion with a charge of -3 is 1s², 2s², 2p⁶, 3s², 3p³
Hence, B. is the correct option.
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If the pH of a weak acid solution is 2.500 and the solution has a concentration of 0.100M, what is the Ka of the weak acid HA?
Answer:
The Kₐ of the weak acid is 1.033×10⁻⁴
Explanation:
The dissociation of a weak acid in aqueous solution is limited to about 5 to 10%
The acid dissociation reaction is given as follows;
HA (aq) + H₂O (l) → H₃O⁺(aq) + A⁻ (aq)
Given that the pH = 2.5, we have
pH = -log₁₀[H₃O⁺] = 2.5
∴ [H₃O⁺] = 10^(-2.5) = 0.0031623
[tex]K_a = \dfrac{[H_3O^+][A^-]}{[HA]}[/tex]
Kₐ = [H₃O⁺][A⁻]/[HA] = (0.0031623^2)/(0.1 - 0.0031623) = 1.033×10⁻⁴
The acid dissociation constant, Kₐ for weak acid is very low as obtained
144g of KCl dissolved in 1000cm3of water at 90oC. Calculate the solubility of KCl at this temperature. (K=39, Cl=35.5, 1dm3=1000cm3).
Answer:
The solubility of KCl is 1.93 mol/dm³
Explanation:
The information given are;
The mass of the potassium chloride, KCl = 144 g
The volume of the water solvent = 1000 cm³ = 1 dm³
The temperature of the solvent = 90 °C
The atomic mass of potassium, K = 39 u
The atomic mass of chlorine, Cl = 35.5 u
The number of moles of potassium in one mole of potassium chloride, KCl = 1 mole
The number of moles of chlorine in one mole of potassium chloride, KCl = 1 mole
The molar mass of the potassium chloride = 39 + 35.5 = 74.5 g/mol
The number of moles, n, of potassium chloride, KCl in 144 g of potassium chloride, KCl is given as follows
n = Mass/(Molar mass) = 144/74.5 = 1.93 moles
1.93 moles will dissolve in 1 dm³
Therefore, the solubility of KCl is 1.93 mol/dm³.
Explain this
When a small piece of glowing sodium is placed inside a gas jar filled with chlorine gas, the sodium continues to burn brightly but when the gas is replaced by argon gas, the glowing sodium becomes extinguished.
Answer:
Because Argon is a inert gas
Explanation:
Inert gases don't take place in any experiments
Answer:
Below.
Explanation:
The sodium reacts strongly with the chlorine to form NaCl and the heat of reaction continues the brightness, whereas it does not react with the inert gas argon and soon cools down.
What are chemical changes of matter?
Answer:
Chemical Changes are also called Chemical Reactions. Chemical reactions involve combining different substances. The chemical reaction produces a new substance with new and different physical and chemical properties. Matter is never destroyed or created in chemical reactions.
Explanation:
Describe how red shifts were used by cosmologists to determine that the universe was expanding. How
is this evidence for the big bang theory?
Explanation:
astronomers have discover that in general the future of a Galaxy is, the more redshift light is this mean that the further away the Galaxy are the faster they are moving this is similar to explosion where the bits moving fastest travel for furthest on the explosion redshift data provides evidence that the universe including space itself is expanding .
An ionic bond is the attraction between _____.
Answer:
oppositely charged ions in a chemical compound
Explanation:
Answer:
Between ions
Explanation:
Which of the following is an aldehyde?
Answer: [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde functional group.
Explanation:
Functional groups are specific group of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.
A. [tex]CH_3CH_2CH_2COCH_3[/tex] has ketone [tex]C=O[/tex] functional group .
B. [tex]CH_3CH_2CH_2COOH[/tex] has carboxylic acid [tex]COOH[/tex] functional group .
C. [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde [tex]H-C=O[/tex] functional group .
D. [tex]CH_3CH_2CH_2COOCH_3[/tex] has ester [tex]RO-C=O[/tex] functional group .
Thus [tex]CH_3CH_2CH_2CHO[/tex] has aldehyde (CHO) group.
what happens when ca no3 2 is heating it gives CaO ,NO2 and 02
Answer:
balanced equation:
2Ca(NO3)2 (aq)-----> 2CaO (s) + 4NO2 (g) + O2 (g)
So heating 2 moles of Ca(NO3)2 gives 2 moles of CaO, 4 moles of NO2 and 1 mole of O2. This is a heat decomposition reaction. It gives a white precipitate (CaO), and brown pungent gas (NO2).
Answer:
The balanced equation of the reaction is below.
Explanation:
2Ca(NO3)2 -----> 2CaO + 4NO2 + O2.
A scuba diver’s air tank contains oxygen, helium, and nitrogen at a total pressure of 205 atmospheres. The partial pressure of nitrogen is 143 atmospheres, and the partial pressure of helium is 41 atmospheres. What is the partial pressure of oxygen in the tank?
answer is 20
explanation: total Pressure = 205
partial pressure of N = 143
partial pressure of He = 41
total pressure = partial pressure of N + partial pressure of O + partial pressure of He
partial pressure of O = 205 - 185 = 20
Answer:
20
Explanation:
Triangle DEF is congruent to TriangleD'EF' by the SSS theorem. Which single rigid transformation is required to map TriangleDEF onto TriangleD'EF'? dilation reflection rotation translation
Answer:
B. reflection
Explanation:
Rigid transformations are methods involved in changing the dimensions or orientation of a given figure. The methods are; dilation, rotation, translation and reflection.
Reflection is the process in which a given figure is turned or flipped with respect to a point or line of reference.
In the given question,
ΔDEF ≅ ΔD'EF' (Side-Side-Side congruence property)
This implies that ΔDEF was reflected about point E to produce ΔD'EF'. Thus the required rigid transformation is reflection.
Answer:
Is C - Rotation
Explanation:
I have right on my test
Determine the rate of a reaction that follows the rate law: rate = k[A]^m[B]^n, where: k = 0.2, [A] = 3 M, [B] = 3 M, m = 1, n = 2 A. 1.2 (mol/L)/s B. 27 C. 1.8 D. 5.4
[tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex] is rate of a reaction when k = 0.2, [A] = 3 M, [B] = 3 M, m = 1, n = 2 .
What is the rate of a reaction?The rate at which the concentration of reactant or product participating in a chemical reaction alters is called the rate of reaction.
Rate of reaction = [tex]\frac{change \;in \;concentration}{time}[/tex] = (mol/litre)/time.
m= 1 and n = 2
[tex]rate = K [A] [B]^2[/tex]
[tex]0.2 = K X 3 X 3 ^2[/tex]
K = [tex]\frac{0.2 }{27 }[/tex]
K = [tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex]
Hence, [tex]7.408 \;X 10 ^ {-3} m^{-2} s^{-1}[/tex] is rate of a reaction when k = 0.2, [A] = 3 M, [B] = 3 M, m = 1, n = 2 .
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Answer: 7.4 10-3
Explanation:
7.4 10-3 this is right ong
The radioactive isotope used for carbon dating is
1. Carbon 12
2. Carbon 13
3. Carbon 15
4. Carbon 14
Carbon 14 would be your answer, however if it's more than one answer it would also be Carbon 12, so yeah. Your best bet would be Carbon 14.
What is meant by 1m length
Answer:
The metre is defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second.
Julie finds a snail on the sidewalk and wants to know whether or not the snail moves throughout the day. She places a
single mark on the sidewalk next to the snail.
What will Julie use the mark for initially?
determining how fast the snail moves
acting as a standard unit of measure
determining the displacement of the snail
O acting as a reference point for detecting motion
The single mark placed on the sidewalk by Julie has been acting as the reference point for detecting the motion of the snail. Thus, option D is correct.
The snail has been the shelled animal that has been mostly residing in the resting condition with limited movement. To evaluate the movement of the snail, there has been the consideration of a point that was the starting point from the movement.
The line that has been set across the sidewalk has been acting as the reference, and the distance traveled has been calculated from that point. Thus, option D is correct.
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What does the pH of a solution have to be in order to be a base?
Explanation:
pH is used to measure the concentration of H+ ions ([H+]) and therefore, whether a substance is acidic or basic (alkaline). Solutions with a pH of less than seven are acidic, while those with a pH greater than seven are basic (alkaline).
Answer:
greater than 7
Explanation:
A base is any solution with a pH greater than 7. A pH of 7 is considered neutral. For example, the pH of water. An acid is any solution with a pH less than 7.
Hope that helps.
Acetic acid only partially ionizes in water. A solution contains a large quantity of acetic acid dissolved in water. How can this acid solution best be described?
Answer:
The acid solution is a concentrated solution.
Explanation:
Acetic acid is a weak acid, because it ionizes partially in water as shown below:
CH3COOH + H2O —> H3O+ + CH3COO-
A solution containing a larger quantity of acetic acid is termed concentrated solution.
This is so because a concentrated solution is a solution that contains more of the solute than the solvent.
A solute is the substance which dissolves in the solvent.
A solvent is the substance which dissolves a solute.
In this case, acetic acid is the solute and water is the solvent.
Solution is simply the combination of solute and solvent
Solution => Solute + Solvent
More solute + Less solvent => Concentrated solution
Therefore, a solution containing a higher quantity of acetic acid ( i.e the solute) in water (i.e the solvent) is called a concentrated solution.
calculate the mass of sodium sulphate required to prepare its 20%of solution in 100 g ofwater
Answer:
25 g
Explanation:
Mass percent implies the mass of solute dissolved in a solution
Mass percent = mass of solute/mass of solute + mass of solvent × 100/1
Since mass percent concentration= 20%
Mass of solvent = 100g
Let mass of solute = x
Hence;
20 = x/x +100 ×100/1
20/100= x/x + 100
0.2 = x/x + 100
0.2(x + 100) = x
0.2x + 20 = x
20 = x - 0.2x
20 = 0.8x
x= 20/0.8
x= 25 g
Which of the following is a halogen?
O A. Neon (Ne)
B. Iodine (1)
O C. Oxygen (0)
O D. Potassium (K)
Answer:
[tex]\boxed{\mathrm{Iodine}}[/tex]
Explanation:
Halogens are elements in group 17 or 7 in the periodic table.
Iodine is a halogen.
Therefore, iodine, an Halogen
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Which of the following is represented by the number of significant figures in a quantity? A) estimation B) precision C) accuracy D) scientific notation
Answer: the answer is B estimation
Explanation:
i just took a test
The one that is represented by the number of significant figures in a quantity is scientific notation. The correct option is D.
What is scientific notation?Scientific notation is a method of expressing numbers that are either too large or too small to be written in decimal form.
In the United Kingdom, it is known as scientific form, standard index form, or standard form.
The proper scientific notation format is an x 10b, where an is a number or decimal number with an absolute value greater than or equal to one and less than ten, or 1 |a| 10. b is the power of ten required for scientific notation to be mathematically equivalent to the original number.
Scientific notation is represented by the number of significant figures in a number.
Thus, the correct option is D.
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what is a chemical bond? an attractive force between 2 molecules
Answer:
The chemical bond between 2 molecules is called an intermolecular force.
Answer:
Chemical Bond:
Attraction between two atoms results in the formation of a bond which is called a chemical bond.
Inter molecular Forces:
Attractive Force that in between 2 molecules is called Inter molecular Forces. (Inter : Between)
Cuantos gramos de sulfato de plomo (II) se requieren para preparar 200mL una solución de esta sal a una concentración de 100 ppm. Si se toma una muestra de 30 mL de la disolución anterior y se diluye en 1000 mL de agua, ¿cuál es la concentración de la disolución?
Answer:
0.020g de sulfato de plomo se requieren
La concentración de la solución diluida es de 3ppm
Explanation:
Las partes por millón (ppm) son definidas como:
miligramos soluto / 1L solución.
Si deseas preparar una solución a 100ppm de sulfato de plomo (II) necesitas 100mg de este sulfato en 1L. En 200mL = 0.200L vas a necesitar:
0.200L × (100mg / 1L) = 20mg de sulfato de plomo (II).
Como 1000mg = 1g,
20mg × (1g / 1000mg) = 0.020g de sulfato de plomo se requieren.
Ahora, se van a tomar 30mL de esta solución y se diluirán a 1000mL. Se diluye la solución:
1000mL / 30mL = 33.33 veces.
Como la solución inicial es de 100ppm, esta dilución genera una solución de concentración:
100ppm / 33.33 = 3ppm
The intake stroke of a positive displacement compressor is most similar to that of a
A. thermostatic expansion valve.
B. auxillary electric water pump.
C. one-stroke variable displacement compressor.
D. two-stroke cylinder engine.
Answer:
D. two-stroke cylinder engine.
Explanation:
Two-stroke cylinder engine: In chemistry, the term "two-stroke cylinder engine" is described as one of the types of "internal combustion engine" that tends to complete a single "power cycle" possessing two different strokes of the "piston" during a particular "crankshaft revolution".
It generally consists of two different strokes that are being often known as power or exhaust and suction stroke.
In the question above, the given statement signifies the "two-stroke cylinder engine".
Research on ‘where a person’s carbon emissions come from inside a home’ and represent the data in the form of a pie chart. Pls answer with pie chart I WILL MARK U AS BRAINSLIEST IF YOU GIVE RIGHT ANSWER
Answer:
Here's what I get from one source.
Explanation:
[tex]\begin{array}{lc}\textbf{Source} &\textbf{Contribution \%} \\\text{Space heating }& 45\\\text{Water heating} &18\\\text{Space cooling} & 9 \\\text{Computers/Electronics} & 6 \\\text{Lighting} & 6 \\\text{Cooking} & 4 \\\text{Refrigeration} & 4 \\\text{Wet cleaning} & 3 \\\text{Other} & 5 \\\end{array}[/tex]
The pie chart is in the Figure below.
how is impure copper refined by electrolysis
Answer:
By giving electricity to copper compound solution.
Explanation:
Electrolysis is one of the major way of refined copper. The copper containing solution has two electrodes.i) positive electrodes called anode. ii) negative electrodes called cathode. When electricity is pass into the copper containing solution electrolysis process is starts and impure copper is formed in anode and pure copper is formed in cathode.
So, We can get pure copper in cathode through electrolysis.
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why the filament of bulb has high melting point
Answer:
The filament of a bulb has a high melting point because of the heat generated inside the bulb.
Explanation:
When electricity is concentrating and run through a bulb, it starts to generate heat. Leave it on long enough and it will start to build up a lot of heat. Have you ever tried touching a light bulb when it has been all day? It's scorching to the skin.
Since electricity generates heat, the bulb's filament has to have a high melting point so it doesn't melt, destroy the bulb, and leave you light-less. If the filament has a high melting point, then it is able to withstand heat generated by electricity and provide you light.
Which of the mechanical waves below has the greatest energy?
Answer:
Blue wave.
Explanation:
The energy of a wave depends on its amplitude. A wave having more amplitude will have greatest energy while a wave having small amplitude will have least energy. The given figure shows four waves that are shown with green, orange, blue and red color. It is very clear from the figure that the amplitude of blue wave is greatest of all the wave.Hence, blue wave will have greatest energy.What evidence suggests that global climate change is causing the oceans to get warmer?
Answer:
A large point of evidence in this would be the rate of increase in how fast the polar ice caps are melting and the ocean is rising as a result. As the climate is getting warmer so are the oceans and this is causing the ice caps which are in the ocean.
Explanation:
What do neurons and protons have in common?
Answer:
Protons and neutrons have almost the same mass and are both located in the nucleus of the atom
Answer:
Protons and neutrons have almost the same mass and are both located in the nucleus of the atom. Protons are charged particles. Neutrons are neutral particles. ... The positive charge of the protons in the nucleus is balanced by the negative charge of the electrons.