Answer:
%abundance of isotope B-11 is 80%, therefore, the %abundance of isotope B-10 is 20%.
Explanation:
The average atomic mass of an element is actually a weighted average atomic mass, taking into account the percent abundance of the naturally occurring isotopes of the element.
To calculate the weighted average mass, you must take the sum of atomic masses of all the naturally occurring isotopes multiplied by their %abundance.
Ave At. Mass = sum of [(isotopic mass)(%abundance)]/100
If we let the %abundance of B-11 be represented by X, then the %abundance of B-10 must be (100-X).
Now we can set up the following equation and solve for X
10.8 = [(10)(100-X) + (11)(X)]/100
1080 = 1000 - 10X + 11X
80 = X
So, the %abundance of isotope B-11 is 80%, therefore, the %abundance of isotope B-10 is 20%.
Pure magnesium metal is often found as ribbons and can easily burn in the presence of oxygen. When 3.28 g of magnesium ribbon burns with 7.25 g of oxygen, a bright, white light and a white, powdery product are formed. Enter the balanced chemical equation for this reaction. Be sure to include all physical states. equation: What is the limiting reactant? magnesium oxygen The reaction goes to completion, but in the process of recovering the product, some of it was lost. The the percent yield for the reaction is 83.7%. How many grams of product are recovered? mass of product recovered: g How many grams of the excess reactant remain? Assume the reaction goes to completion. mass of excess reactant: g
Answer:
2 Mg(s) + O2(g)→ 2 MgO(s)
Explanation:
Number of moles of magnesium reacted = mass/ molar mass = 3.28g/24gmol-1 = 0.137 moles
From the balanced reaction equation;
2 moles of Mg yields 2 moles of MgO
0.137 moles of Mg yields 0.137 moles of MgO
For oxygen;
Number of moles of oxygen reacted = mass/ molar mass = 7.5g/32gmol-1 = 0.234 moles of O2
If 2_moles of oxygen yields 2 moles of MgO
0.234 moles of oxygen yields 0.234 moles of MgO
Hence Mg is the limiting reactant
Theoretical yield of MgO = 0.137 moles × 40 gmol-1 = 5.48 g of MgO
% yield of MgO = 83.7%
But
% yield = actual yield/theoretical yield × 100
actual yield = % yield × theoretical yield / 100
actual yield= 83.7 × 5.48/100
Actual yield = 4.59 g
According to the equation;
2 moles of Mg reacts with 2 moles of oxygen
Hence 0.137 moles of Mg will react with 0.137 moles of O2
Amount of excess reactant = 0.234 moles - 0.137 moles = 0.097 moles
Mass of excess reactant = 0.097 moles × 32gmol-1 = 3.1g of O2
number of SO42- ions in 20.4 g Cr2(SO4)3
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One mole of or 392 g of chromium sulphate gives 3 moles of sulphate ions. Thus 30 g of chromium gives 0.15 moles of sulphate ions or 9.39 ×10²² ions.
What are ions?Ions are charged substances formed by electron lose or gain by an atom. If an atom gain an electron it acquire one unit of negative charge and if it lose an electron it acquires a positive charge.
The ionization of chromium sulphate is written as follows:
[tex]Cr_{2}(SO_{4})_{3} \rightarrow 2Cr^{3+} + 3SO_{4}^{2-}[/tex]
Hence, one moles of chromium sulphate forms 3 moles of sulphate ions. One mole of chromium sulphate is 392.18 g/mol. Thus number of moles 20.4 g of the compounds is 20.4 / 392.18 = 0.052 moles.
The number of moles of sulphate ions produced by 0.052 moles of chromium sulphate is calculated as follows:
0.052 × 3 = 0.15 moles.
One mole of sulphate ion contains 6.022 × 10 ²³ions. Thus number of ions in 0.15 moles is 0.15 ×6.022 × 10 ²³ = 9.39 ×10²² ions.
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How many moles in 6.4 g of H2O?
46 mol
124 mol
.025 mol
.36 mol
Explanation:
Given
Weight of Water (H2O) = 6.4 gms
To find
Number of moles of water = ?
Solution
we know that molar mass of H2O = 18 g
Now,
[tex]Number \: of \: moles =\frac{Given \: weight \: of \: substance}{molar \: mass \: of \: substance} [/tex]
Number of moles = 6.4/18 = 0.355~ 0.36 moles
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Answer:
Explanation:
h2o = 18 gmol-1
1mol =18 g
18 g =1mol
6.4g =1/18*6.4
= 0.355
=0.36mol
Which electromagnetic wave has lowest frequency and shortest wavelength
Which two forms of heat transfer work together to heat water in a plastic bottle?
a. reflection and convection
b. conduction and convection
c. radiation and reflection
d. convection and reflection
Definitions of heat and work
Answer:
Hear is the transfer of thermal energy between system.
Work is the transfer of mechanical energy between two systems.
How should scientists set up the control group in this experiment?
Answer:
Please show a file so I can answer your question or tell me which experiment.
Explanation:
Definition:The control group (sometimes called a comparison group) is used in an experiment as a way to ensure that your experiment actually works. It's a way to make sure that the treatment you are giving is causing the experimental results, and not something outside the experiment.
Q. An ingestion tablet contains a mass of 0.30 g of hydroxide [Mg(OH)2] as its only basic ingre magnesium dient. The balanced chemical equation between magnesium and hydrochloric acid (HCl(aq)), the acid produced in the stomach is as follows:
Mg(OH)2(aq) + 2HCl(aq) ⟶ MgCl2(aq) + 2H2O(l)
(i) Calculate the volume of 1.00 M HCl neutralised by two of these ingestion tablets?
(ii) What mass of the salt is formed in this neutralisation reaction?
(iii) How many magnesium ions are present in this amount of a salt?
(i) The volume of 1.00 M HCl neutralized by two of these ingestion tablets is 20.6 mL
(ii) The mass of salt formed in the neutralization reaction is 0.98 g
(iii) The number of magnesium ions present in that amount of salt is 6.19 × 10²¹ ions
Stoichiometry(i) From the question, we are to calculate the volume of 1.00 M HCl neutralized two of the ingestion tablets
From the given balanced chemical equation
Mg(OH)₂(aq) + 2HCl(aq) ⟶ MgCl₂(aq) + 2H₂O(l)
This means,
1 mole of Mg(OH)₂ is neutralized by 2 moles of HCl to give 1 mole of MgCl₂
Now, we will determine the number of moles of Mg(OH)₂ present in two of the ingestion tablets
From the given information
Mass of Mg(OH)₂ in 1 ingestion tablet = 0.30 g
∴ Mass of Mg(OH)₂ in 2 ingestion tablets = 0.60 g
Using the formula,
[tex]Number\ of\ moles = \frac{Mass}{Molar\ mass}[/tex]
Molar mass of Mg(OH)₂ = 58.33 g/mol
Then,
Number of moles of Mg(OH)₂ in 2 ingestion tablets = [tex]\frac{0.60}{58.33}[/tex]
Number of moles of Mg(OH)₂ in 2 ingestion tablets = 0.0102863 mole
Now,
If 1 mole of Mg(OH)₂ is neutralized by 2 moles of HCl
Then,
0.0102863 mole of Mg(OH)₂ will be neutralized by 0.0205726 moles of HCl
∴ The number of moles of HCl that would neutralize 2 ingestion tablets is 0.0205726 mole
Now, for the volume of 1.00 M HCl neutralized by two ingestion tablets
Using the formula,
[tex]Volume = \frac{Number\ of\ moles}{Concentration}[/tex]
Volume = [tex]\frac{0.0205726}{1.00}[/tex]
Volume = 0.0205726 L
Volume = 20.5726 mL
Volume ≅ 20.6 mL
Hence, the volume of 1.00 M HCl neutralized by two of these ingestion tablets is 20.6 mL
(ii) For the mass of salt (MgCl₂) formed in the neutralization reaction
Since 1 mole of Mg(OH)₂ is neutralized by 2 moles of HCl to give 1 mole of MgCl₂
Then,
0.0102863 mole of Mg(OH)₂ will be neutralized by 0.0205726 moles of HCl to give 0.0102863 mole of MgCl₂
∴ The number of moles of the salt (MgCl₂) formed is 0.0102863 mole
For the mass of the salt formed,
Using the formula,
Mass = Number of moles × Molar mass
Molar mass of MgCl₂ = 95.211 g/mol
∴ Mass = 0.0102863 × 95.211
Mass = 0.9793689 g
Mass ≅ 0.98 g
Hence, the mass of salt formed in the neutralization reaction is 0.98 g
(iii) For the number of magnesium ions present in that amount of salt,
1 mole of MgCl₂ contains 1 mole of magnesium ions
Then,
0.0102863 mole of MgCl₂ will contain 0.0102863 mole of magnesium ions
From the formula,
Number of ions = Number of moles × Avogadro's constant
Avogadro's constant = 6.022 × 10²³ mol⁻¹
∴ Number of magnesium ions present = 0.0102863 × 6.022 × 10²³
Number of magnesium ions present = 0.061944 × 10²³
Number of magnesium ions present = 6.1944 × 10²¹
Number of magnesium ions present ≅ 6.19 × 10²¹ ions
Hence, the number of magnesium ions present in that amount of salt is 6.19 × 10²¹ ions
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The density of copper is 8.68 g/mL use the density value to determine how many moles are
contained in a 125 mL sample.
Answer:
17.1 mol
Explanation:
(8.68g/mL * 125 mL) = 1085 g
1085 g/ (63.55 g/mol) = 17.1 mol
What cells do you think is in metaphase? why?
A large beaker has 6.75 L of a solution containing 5.25 moles of copper (II) sulfate in water. What is the molarity of the solution?
A: 9.9 M
B: 10 M
C: .78 M
D: 8M
The molarity of the solution in a large beaker that has 6.75 L of a solution containing 5.25 moles of copper (II) sulfate in water is 0.78M.
How to calculate molarity?The molarity of a solution can be calculated using the following formula:
M = n/V
M = molarity of solutionn = number of moles V = volume of solutionMolarity = 5.25/6.75
Molarity = 0.78M
Therefore, the molarity of the solution in a large beaker that has 6.75 L of a solution containing 5.25 moles of copper (II) sulfate in water is 0.78M.
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state three reasons why air is
•Chassifield as a mixture
One is through sublimation
Answer:
Air is considered as a mixture because it is composed of various separate components. The air has no characteristic properties of its own. ur welcome :)
Explanation:
write the reaction for ferric hydroxide dissolving in NaOH. hint combine the two equilibrium reaction
The properly balanced chemical equation for this chemical reaction is written as follows:
[tex]FeCl_{3}(aq)+3Na0H(aq) \rightleftharpoons Fe(OH)_3(s)+3NaCl(aq)[/tex]
What is a chemical reaction?A chemical reaction can be defined as a chemical process that involves the continuous transformation (rearrangement) of the ionic, atomic or molecular structure of a chemical element by breaking down and forming chemical bonds, in order to produce a new chemical compound while new bonds are formed.
The chemical reaction of aqueous ferric hydroxide that is dissolved in aqueous sodium hydroxide produces ferric hydroxide and aqueous sodium chloride. Thus, the properly balanced chemical equation for this chemical reaction is written as follows:
[tex]FeCl_{3}(aq)+3Na0H(aq) \rightleftharpoons Fe(OH)_3(s)+3NaCl(aq)[/tex]
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The nutrition label tells us that 13 g of a serving of gummy bears (i.e. 10 gummy bears) is made of sugars. Let's assume that all of the sugar is sucrose. The balanced reaction for the combustion of sucrose is given below. How much heat is released from the combustion of the sucrose in a single gummy bear?
2C12H22O11+24O2→24CO2+22H2O ΔHrxn=−11,286kJ
This problem is providing the mass of gummy bears which are assumed to contain 13 g of sucrose, which undergoes combustion and produces -214.3kJ of heat according to the following:
Heat of reactionIn chemistry, when a fuel undergoes combustion, a reaction with oxygen, it produces carbon dioxide and water in a complete combustion. In such a way, with the given reaction, we can write the heat of reaction as -11,286 kJ per mole of reaction:
[tex]\Delta H=-11,286\frac{kJ}{mol\ rxn}[/tex]
Which means that if we need the total heat released by 13 g of sucrose, one must apply the following dimensional analysis including this fuel's molar mass (342.3 g/mol):
[tex]Q=-11,286\frac{kJ}{mol\ rxn}*\frac{1mol\ rxn}{2molC_1_2H_2_2O_1_1}*13gC_1_2H_2_2O_1_1 *\frac{1molC_1_2H_2_2O_1_1}{342.3gC_1_2H_2_2O_1_1} \\\\Q=-214.3kJ[/tex]
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3. Materials that easily break when a force is applied like glass are said to be
A. malleable B: brittle C. ductile D. elastic
4. Which of the materials below is a poor conductor of heat?
A Iron B. Wood C. Gold D. Copper
5. is the characteristic or trait that can be observed when a matter reacts to
another substance,
A. Intensive Physical Property
C. Chemical Property
B. Extensive Physical Property D. Physical Property
6. property is the characteristic or trait of matter that does not depend on the amount.
A. Intensive Physical Property
C. Chemical Property
B. Extensive Physical Property D. Physical Property/
7. is the characteristic or trait of matter that can be observed or perceived with our senses easily
without changing its chemical composition.
A Intensive Physical Property
C. Chemical Property
B. Extensive Physical Property D. Physical Property
8. Phase of matter where particles are relatively far apart and practically independent of each other.
A. Solid B. Liquid C. Gas D. Plasma
Cloccify the following pyamnles as pure substance or mixture:
Answer:
3. B
4. B
5. C
6. A
7. D
8. C
Explanation:
3. A material or substance is said to be BRITTLE If it can be broken easily when there is an application of force e.g glass
4. A material that cannot conduct heat and electricity is called an INSULATOR. Among the given options, WOOD is a poor conductor of heat i.e. it cannot withstand hear. Iron, gold and copper are all metals, hence, very good conductors.
5. Matter which constitutes all substances tend to react with one another, however, when the observed trait or characteristic is called a CHEMICAL PROPERTY.
6. Physical property of matter can either be intensive or extensive. INTENSIVE PHYSICAL PROPERTY is that characteristic or trait of matter that does not depend on the amount. Example is temperature, density etc
7. PHYSICAL PROPERTY is the property of matter that can be observed or perceived with our senses easily without changing its chemical composition or nature. Example of physical property is melting.
8. Matter exists in three states; solid, gas and liquid. In the GASEOUS state of matter, particles are relatively far apart or scattered and practically independent of each other. This allows gas to be able to diffuse.
predict the block, period and group of (Z:12)
Explanation:
Atomic number = 12
Block = s-block
Period = 3rd
Group = 2nd
Determine the number of moles of CO2 that contain 7.93 x 1023 O atoms.
Answer:
This question requires use of Avogrado’s constant that states there are 6.02 x10^23 constituent particles contained in the amount of a substance given by one mole. Constituent particles are usually molecules, ions or atoms. Therefore there are 18.06x10^23 total atoms, 12.04x10^23 oxygen atoms, 6.02x10^23 carbon atoms and 6.02x10^23 carbon dioxide molecules.
A red shirt obsorbs red light true or false
Answer:
A red shirt appears red to our eyes because the shirt absorbs the red wavelengths of visible light. The shorter the wavelength of light, the more energy it has.
Explanation:
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Fill in the blanks with its definition or description.
a. _________ The point in a titration when the added amount of standard reagent is equal to the amount of analyte being titrated.
b. _________The analyte is titrated with the standard reagent and the volume of standard solution required to complete the reaction is measured.
c. _________A reagent that is pure and stable, which can be used directly after weighing.
d. _________The analyte that is being analyzed in the titration.
e. _________Standard reagent is added in excess to ensure complete reaction with the analyte.
f. _________The excess reagent is then titrated with a second standard reagent.
g. _________A solution, whose concentration is known, often made from a reagent of known purity.
h. _________The standard reagent of known concentration that is added from a buret to the analyte solution.
i. _________The analyte does not react directly with the titrant so it is converted to another form which will react with the titrant.
j. _________The point in a titration when a change in the analyte solution is observed, indicating equivalency.
k. _________It is added to the analyte solution and aids in the observation of the completion of the reaction.
Answer:
a) equivalence point
b) direct titration
c) primary standard
d) titrand
e) Back titration
f) back titration
g) standard solution
h) standard solution
I) indirect titration
j) end point
Explanation:
A volumetric analysis is one in which a solution of unknown concentration is determined from its volume. This is commonly referred to as titration.
In titration, a standard solution is reacted with another solution of unknown concentration. The point at which the concentration of the standard solution is equal to that of the analyte is known as the equivalence point (usually indicated by a colour change). An indicator may be added to the analyte solution to help identify when the reaction is complete.
Guys i need help with these questions! I will give brainliest to the first person who answers
what about this?
Which of these best explains the distribution of natural resources?
A. Resources are distributed evenly across Earth's systems.
B. Resources are distributed where they are needed by humans.
C. Resources are distributed unevenly and often must be moved for human use.
D. Resources are located in areas where they can be transported without damage to the environment.
Answer:
c
Explanation:
resources are distributed unevenly and often must be moved for human use
Answer:c
Explanation: correct on edg 2020
Estimate the molar concentration of 0.50 wt% (0.0050 mass fraction) benzene (C6H6) dissolved in liquid ethanol (C2H5OH) at 20°C. The density of liquid ethanol is 789 kg/m3 at 20°C. This solution of the solute benzene dissolved in the solvent ethanol is considered dilute.
The molar concentration of benzene is 0.05mol/L
Data;
Mass Fraction = 0.0050Temperature = 20°CDensity of Ethanol = 789 kg/m^3 Molar Concentration of Benzenemolar mass of benzene = 78g/mol
molar mass of ethanol = 46g/mol
mole fraction of benzene is
[tex]mole fraction = \frac{moles of benzene}{total mole}[/tex]
Let's substitute the values and find the mole fraction of benzene
[tex]_yC_6H_6 = \frac{\frac{0.005}{78} }{(\frac{0.005}{78})+ (\frac{1-0.005}{46}) }\\ _yC_6H_6 = 0.00295[/tex]
The density of benzene given is 789 kg/m^3
Molar concentration of the solution is
[tex]M = \frac{789}{0.046} = 17.15Kmol/m^3[/tex]
The concentration of benzene is the product of mole fraction and the molar concentration of the solution
[tex]M = 0.00295 * 17.152 = 0.05Kmol/m^3= 0.05mol/L[/tex]
The molar concentration of benzene is 0.05mol/L
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explain how heat is related to thermal energy
Answer: Heat energy is another name for thermal energy.
Explanation:
As thermal energy comes from moving particles, it is a form of kinetic energy. Thermal energy comes from a substance whose molecules and atoms are vibrating faster due to a rise in temperature.
Answer:
When a substance heats up, the rise in temperature makes these particles move faster and bump into each other. Thermal energy is the energy that comes from the heated up substance. The hotter the substance, the more its particles move, and the higher its thermal energy.
a competition between a given substance and its dissolved species is ?
Answer:
Explanation:
It is odd to describe the presence of a given substance and its dissolved species as a competition but the state is called an equilibrium in solubility.
Answer:
Solubility
Explanation:
Mark that
The amount of given substance and dissolved species is constant at equilibrium .
As per le ch atler's principle
If you change the concentration it would affect the Equilibrium n
Write a balanced chemical equation (using subscripts and an arrow) and noting all physical states for the reaction of chlorine gas and ozone gas (O3) to produce chlorine monoxide gas and oxygen gas.
Answer:
O3 => CLO + O2
Explanation:
ozone gas yields one Chlorine Monoxide gas, and two Oxygen gas. i forgot how to explain it well, but I know how to do it and will help in the future if needed :)
How many particles are in 56 L of nitrogen gas at standard conditions?
0 1.2 x 1023 particles
O 2.5 particles
O 1.5 x 1024 particles
O 2.5 x 1024 particles
Answer:
The molar mass of N
2
is 28 g/mol.
56 grams of N
2
=
28g/mol
56g
=2moles
At STP, 1 mole of any gas occupies a volume of 22.4 L.
2 moles of N
2
at STP will occupy a volume of 2×22.4=44.8L
59 Q.No. 28 b Hydrogen peroxide can act as oxidizing as well as reducing agent with example.
Answer:
Hydrogen peroxide can function as an oxidizing agent as well as reducing agent.
H2O2 act as oxidizing agent in acidic medium.
Explanation:
Example : 2FeSO4 +H2SO4 +H2O2 —>
(ferrous sulphate)
Fe2(SO4)3 +2H2O
(ferric sulphate)
Which is defined as the energy required to remove an electron from an atom of an element?
A electronegativity
B ionization energy
C ionic radius
D law of octaves
In photosynthesis, carbon dioxide (CO2) and water (H20) combine to form the sugar glucose (C6H1206) in the following reaction:
6CO2 + 6H20 - CH1206+?
Assuming this equation is balanced, which part is missing from the product side?
-12 hydrogen atoms
-06 carbon atoms
-6 oxygen atoms
-12 oxygen atoms
The part that is missing from the product side = 6 oxygen atoms.
The equation of photosynthesisPhotosynthesis is the process by which green plants traps in energy from the sun, through their chlorophyll, which they use in the manufacture of sugar with oxygen as a by-product.
The balanced equation of photosynthesis;
6CO2 + 6H2O + (energy) → C6H12O6 + 6O2
From the equation given,
6CO2 + 6H20 - CH1206+?
The missing part of the product = 6O2 (-6 oxygen atoms)
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How many moles in 109.6 g of Cl₂?
Answer:
1 grams Cl2 is equal to 0.014103178856514 mole.
Explanation:
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