Answer:
The correct answer is HOF gas.
Explanation:
Based on the given information, the helium atoms effuses three times faster in comparison to the gas X.
The rate of effusion is determined by,
r is inversely proportional to 1/√M, here M is the molecular mass of the gas.
and r is inversely proportional to 1/t, here t is the time taken for effusion.
Thus, t is directly proportional to √M
The molecular mass of He is 4.
tHe = tX/3 (Here tx is the time taken for gas X)
The molecular mass of X is not known.
tX/tHe =√Mx/MHe
3 = √Mx/4
By squaring both the sides we get,
9 = Mx/4
Mx = 36
36 is the molecular mass of gas HOF, that is, (1+16+19 = 36). Hence, the gas X is 36.
Determine whether each observation describes a chemical or a physical property. 1. When a piece of sodium metal is placed in a test tube with water, the sodium zees and bubbles of gas are formed. 2. When table salt is added to water in a test tube, the table salt dissolves. . 3. When a glass marble is heated and then quickly cooled, it shatters. *
1.Sodium metal reacts rapidly with water to form a colorless solution of sodium hydroxide ... strip is placed in a test tube containing 5 mL of hydrochloric acid, HCl. Both liquids ... If it fizzes and bubbles
2.When salt is mixed with water, the salt dissolves because the covalent bonds of water are stronger than the ionic bonds in the salt molecules.
3.When platinum is heated, then cooled to its original state, we say this is a physical change. 19. ... Scratches glass. Sour taste ... A bar of lead is more easily bent than is a bar of aluminum of the same size.
The law of conservation of mass can be demonstrated by a chemical reaction. Which of the
following models of a chemical reaction best represents the law of conservation of mass?
Answer : It’s C.
Cccccccccccccccccccccccccccccccccccccccc
The model of the chemical reaction that best represent the law of conservation of mass is the model with a balanced equation.
The correct answer to the question is the third option.
The law of conservation of matter states that matter can neither be created nor destroyed during a chemical reaction but can be transferred from one form to another.The statement above, suggest that unbalanced equation simply means matter has been created or destroyed.
Therefore, the correct answer to the question given above will be the option in which the equation is balanced.
The option with a balanced equation is the third option.
See attachment photo.
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An unknown weak base with a concentration of 0.0910 M has a pH of 10.50. What is the Kb of this base
Answer: The [tex]K_b[/tex] for the weak base is [tex]3.5\times 10^{-3}[/tex]
Explanation:
[tex]A^-+H_2O\rightarrow HA+OH^-[/tex]
cM 0 0
[tex]c-c\alpha[/tex] [tex]c\alpha[/tex] [tex]c\alpha[/tex]
So dissociation constant will be:
[tex]K_b=\frac{[HA][OH^-]}{[A^-]}[/tex]
[tex]K_b=\frac{(c\alpha)^{2}}{c-c\alpha}[/tex]
Given :
c= 0.0910 M and pH = 10.50
pOH = 14-pH = 14-10.50 = 3.5
Also [tex]pOH=-log[OH^-][/tex]
[tex][OH^-]=antilog(-3.5)= 3.2\times 10^{-4}M[/tex]
[tex][OH^-]=c\alpha=3.2\times 10^{-4}[/tex]
[tex]K_b=\frac{(3.2\times 10^{-4})^2}{(0.0910-3.2\times 10^{-4}}[/tex]
[tex]K_b=\frac{(3.2\times 10^{-4})^2}{(0.09068}[/tex]
[tex]K_b=3.5\times 10^{-3}[/tex]
Thus [tex]K_b[/tex] for the weak base is [tex]3.5\times 10^{-3}[/tex]
The Kb for the unknown weak base is 3.5 × 10⁻³.
How we calculate the dissociation constant for a weak base?Dissociation constant for a weak base at equilibrium is the ratio of the product of concentration of product to the concentration of un-ionized base.
Chemical reaction for a weak base at initial and equilibrium state can be represented as follow:
[tex]\[\mathop {{{\rm{A}}^{\rm{ - }}}}\limits_{\scriptstyle{\rm{c}}\hfill\atop\scriptstyle{\rm{c - c\alpha }}\hfill} {\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{O}}\mathop { \to {\rm{HA}}}\limits_{\scriptstyle{\rm{0}}\hfill\atop\scriptstyle{\rm{c\alpha }}\hfill} {\rm{ + }}\mathop {{\rm{O}}{{\rm{H}}^{\rm{ - }}}}\limits_{\scriptstyle{\rm{0}}\hfill\atop\scriptstyle{\rm{c\alpha }}\hfill} \][/tex]
Kb = [HA] [OH⁻] / [A⁻]
Kb = (c∝)² / (c - c∝)
In the question given that,
pH = 10.50
Concentration of weak base c = 0.0910 M
We know that, pOH = 14 - pH
pOH = 14 - 10.50 = 3.5
Also we now that,
pOH = -log[OH⁻]
[OH⁻] = c∝ = antilog (-3.5) = 3.2 × 10⁻⁴ M
Now we put all these values in the above equation of Kb, we get
Kb = (3.2 × 10⁻⁴)² / (0.0910 - 3.2 × 10⁻⁴) = 3.5 × 10⁻³
Hence, 3.5 × 10⁻³ is the value of Kb.
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Hydrazine reacts with oxygen according to the following equation: N2H4(g) +O2(g) → N2(g) + 2 H2O(l) How many L of N2, measured at 34.9 °C and 755.08 torr, will be produced at the same time that 914.894 g of H2O is produced?
Answer:
V ≈ 646.50 L
General Formulas and Concepts:
Chemistry - Gas Laws
Reading a Periodic TableStoichiometryCombined Gas Law: PV = nRTR constant - 62.4 (L · torr)/(mol · K)Kelvin Conversion: K = °C + 273.15Explanation:
Step 1: Define
RxN: N₂H₄ (g) + O₂ (g) → N₂ (g) + 2H₂O (l)
Given: 34.9 °C, 755.08 torr, 914.894 g H₂O
Step 2: Identify Conversions
Kelvin Conversion
Molar Mass of H - 1.01 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of H₂O - 2(1.01) + 16.00 = 18.02 g/mol
Step 3: Convert
Stoichiometry: [tex]914.894 \ g \ H_2O(\frac{1 \ mol \ H_2O}{18.02 \ g \ H_2O} )(\frac{1 \ mol \ N_2}{2 \ mol \ H_2O} )[/tex] = 25.3955 mol N₂
Temperature: 34.9 + 273.15 = 308.05 K
Step 4: Find Volume
Substitute variables: (755.08 torr)V = (25.3955 mol)(62.4 (L · torr)/(mol · K))(308.05 K)Multiply: (755.08 torr)V = 488160 L · torrIsolate V: V = 646.502 LStep 5: Check
We are given 5 sig figs as our lowest. Follow sig fig rules and round.
646.502 L ≈ 646.50 L
barium chloride + sodium phosphate
Answer with double displacement
Answer:
Barium chloride + Sodium phosphate → barium phosphate + sodium chloride
Explanation:
Double replacement:
It is the reaction in which two compound exchange their ions and form new compounds.
AB + CD → AC +BD
Chemical equation:
BaCl₂ + Na₃PO₄ → Ba₃(PO₄)₂ + NaCl
Balanced chemical equation:
3BaCl₂ + 2Na₃PO₄ → Ba₃(PO₄)₂ + 6NaCl
The cation and anion of both reactants are exchanged with each other.
Ba²⁺ react with PO₄³⁻ and form Ba₃(PO₄)₂ while Cl⁻ react with Na⁺ and form sodium chloride.
Molecular equation:
Barium chloride + Sodium phosphate → barium phosphate + sodium chloride
Which gas law is represented by the following equation: P1/T1 = P2/T2
O none of these
Avogadro's law
Charles's law
Gay-Lussac's law
Boyle's law
Answer:
none of these
Explanation:
The expression:
P1/T1 = P2/T2 is a derivative of the combined gas law.
From the combination of the Boyle's and Charles's law, if the volume is taken to be constant, the pressure of the given mass of gas is directly proportional to the absolute temperature.
This is how the expression
P1/T1 = P2/T2 was obtained.
When equal moles of an acid and a base are mixed, after reaction the two are compounds are said to be at the _______________.
Answer: equivalence point
When equal moles of an acid and a base are mixed, after reaction the two are compounds are said to be at the equivalence point.
The equivalence point is called the moment when the equivalents of the titrated substance and those of the titrant substance are equal.
When a strong acid is neutralized with a strong base, the pH undergoes a sharp change just at the equivalence point.
At the time of neutralization, it is true that the number of equivalents of acid that have reacted is equal to the number of equivalents of the base.
This equivalence point is very easily detected since a sharp pH jump is observed in its vicinity, which can be detected in a pH meter or with an indicator.
Therefore, we can conclude that the equivalence point of a reaction is the point at which an equivalent amount of acid and base has been added.
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Scientific notation.
Answer:
The answer is 2.31×10^12
Explanation:
(4.2×10^9)(5.5×10^2)
(4.2×5.5)×(10^9×10^2)
23.1×10^9+2
23.1×10^11
Answer:2.31×10^12
A 0.4708 g sample of a pure soluble bromide compound is dissolved in water, and all of the bromide ion is precipitated as AgBr by the addition of an excess of silver nitrate. The mass of the resulting AgBr is found to be 0.9093 g. What is the mass percentage of bromine in the original compound
Answer:
The correct answer is 82.18%.
Explanation:
Based on the given information, the mass of the pure soluble bromide compound is 0.4708 grams, and the mass of the formed silver bromide is found to be 0.9093 grams.
The molecular weight of AgBr is 187.77 g/mol, and the molecular weight of Br is 79.9 g/mol.
So, 0.9093 grams of AgBr comprise (79.9 * 0.9093)/187.77 = 0.3869 grams of bromine.
Now, 0.4708 grams of sample comprise 0.3869 grams of bromine. Therefore, 100 grams of sample comprise (0.3869*100) / 0.4708 g = 82.18 grams of bromine.
The mass % of bromine in the original compound is 82.18%.
Consider a copper-zinc corrosion couple. If the current density at the copper cathode is 0.05 A/cm2, calculate the weight loss of zinc per hour if the copper cathode area is 100 cm2 and the zinc anode area is 1 cm2 . Group of answer choices 0.061 g/h 6.1 g/h 61 g/h
Answer: the weight loss of zinc per hour is 6.1 g/h
Option c) 6.1 g/h is the correct answer.
Explanation:
Given that
copper cathode area is = 100 cm²
zinc anode area = 1 cm²
current density at the copper cathode = 0.05 A/cm²
The corrosion current can be converted to a rate of metal loss from its surface by using Faraday's law
W = ItM / nF
W is weight loss of metal , I is current ,
I = iCu × ACu = 0.05 A/cm² x 100 cm² = 5.0 A
M is atomic weight of metal
Atomic mass of Zn = 65.38 g/mol
n = number of electron
F = Faraday’s constant = 96,500 C/mol
so we substitute
W loss of Zn = (5 A) × (3600/h) (65.38 g/mol) / [2 × (96,500 C/mol) ]
= 1176840 / 193000
= 6.098 ≈ 6.1 g/h
Therefore the weight loss of zinc per hour is 6.1 g/h
Option c) 6.1 g/h is the correct answer.
How many aluminums are in the chemical formula of 2AI²(S0³)³?
Answer:
4
General Formulas and Concepts:
Chemistry
Identifying Moles/Atoms and CompoundsExplanation:
Step 1: Define
Al₂(SO₃)₃ - Aluminum Sulfide
2Al₂(SO₃)₃
Step 2: Identify
In Aluminum Sulfide, we have 2 Al's for every 3 SO₃²⁻'s.
So far, we have 2 Al's in total.
BUT, since we have a 2 coefficient in 2Al₂(SO₃)₃, we need to multiply by 2.
Therefore, we have 4 Al's in total.
The wavelength of the blue light given off by a mercury vapor street lamp is 457 nm. What is the frequency of this light in hertz (s^ -1 )? pls help
Answer:
6.56×10¹⁴ Hz
Explanation:
From the question given above, the following data were obtained:
Wavelength = 457 nm
Frequency =?
Next, we shall convert 457 nm to metre (m). This can be obtained as follow:
1 nm = 1×10¯⁹ m
Therefore,
457 nm = 457 nm × 1×10¯⁹ m / 1 nm
457 nm = 4.57×10¯⁷ m
Thus, 457 nm is equivalent to 4.57×10¯⁷ m
Finally, we shall determine the frequency of the blue light as follow:
Wavelength = 4.57×10¯⁷ m
Velocity of light = 3×10⁸ m/s
Frequency =?
Velocity = wavelength x frequency
3×10⁸ = 4.57×10¯⁷ × frequency
Divide both side by 4.57×10¯⁷
frequency = 3×10⁸ / 4.57×10¯⁷
frequency = 6.56×10¹⁴ Hz
Therefore, the frequency of the blue light is 6.56×10¹⁴ Hz
What must be known for the rate constant to be calculated from the rate law?
A. The temperature at the beginning if the reaction
B. The reaction rate at known product concentrations
C. The reaction rate at known reaction concentrations
D. The activation energy the reaction must overcome
Answer:
C. The reaction rate at known reaction concentrations
Explanation:
The rate of a reaction is the measure of the speed of a chemical reaction. To find the rate constant of a reaction, the concentration of the reactants must be known.
Reaction rate is directly proportional to the concentration of the reactants. The quantitative relationship between the rate of a reaction and the concentrations of reactants is expressed as the rate law. From this we can deduce the rate constant.Answer:
C. ApE x Approved
Explanation:
Trust
Based on the information that is given, which atom is the table ?
Answer:
The one with the greatest mass would be the one that has the most things in the nucleus, protons and nutrons
Explanation:
What is the anion in the chemical formula MnSe2?
Which chemical reaction involves the fewest oxygen atoms?
A. 2AgNO3 + K2SO4 → Ag2SO4 + 2KNO3
B. 4Fe + 6H2O + 302 4Fe(OH)3
C. 6CO2 + 6H20 - C6H12O6 + 602
D. C2H4 + 302 - 2CO2 + 2H2O
Answer:
4Fe + 6H2O + 3O2 -------> 4Fe(OH)3
Explanation:
The chemical reaction involves the fewest oxygen atoms is 4Fe + 6H2O + 302 4Fe(OH)3. Therefore, option B is correct.
What is chemical reaction ?The chemical reaction, the transformation of one or more chemicals (the reactants) into one or more distinct compounds (the products). Chemical elements or chemical compounds make up substances.
When atoms establish or break chemical bonds, chemical processes take place. Reactants are the substances that begin a chemical reaction, while products are the compounds that are created as a result of the reaction.
We can learn about a substance's qualities by studying chemical reactions. We can learn about a substance's chemical characteristics by looking at how it interacts with other substances. These characteristics can be utilized to recognize an unidentified sample.
Thus, option B is correct.
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You are given 10ml (M) 20 Naoh solution in a conical flask and asked to titrate with (M) 20 Hcl and (M) 20 H2so4 separately. calculate the moles of Hcl and H2so4 required to neutralize the Naoh solution
Answer:
[tex]n_{HCl}=0.2molHCl\\n_{H_2SO_4}=0.1molH_2SO_4[/tex]
Explanation:
Hello!
In this case, since the reactions between NaOH and the acids are:
[tex]NaOH+HCl\rightarrow NaCl+H_2O\\\\2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O[/tex]
Whereas we can see the 1:1 and 2:1 mole ratios between NaOH and HCl and H2SO4 respectively. In such a way, at the equivalence point we realize that:
[tex]n_{HCl}=n_{NaOH}=V_{NaOH}M_{NaOH}=0.01L*20mol/L=0.2molHCl\\\\2n_{H_2SO_4}=n_{NaOH}\\\\n_{H_2SO_4}=\frac{1}{2} V_{NaOH}M_{NaOH}=\frac{0.01L*20mol/L}{2} =0.1molH_2SO_4[/tex]
Best regards!
If you have 25 pieces of bread and 9 pieces of turkey and a turkey
sandwich is made from 2 pieces of bread and 1 piece of turkey, what is the
limiting reagent?
Turkey plus bread
None of these
Bread
Turkey
Every cell in an organism has the same number of chromosomes, except:
A.)Skin cells
B.)Neurons
C.)White blood cells
D.)Reproductive cells
Answer: omg this is so old! :D but its D!
Explanation:
The cells that has been composed of the indifferent number chromosomes as compared to other cells have been reproductive cells. Thus, option D is correct.
Cells have been the smallest and the unit of life. The cells have been composed of the pairs of chromosomes in higher organisms. There has been the presence of 46 chromosomes i.e. 23 pairs of chromosome. However, the chromosomes in the cell have been diploid i.e. in set of 2.
The reproductive cells have been resulted in the formation of the new cells. So they have been consisted of the cells with the half the number of chromosomes and are haploid in nature.
Thus, the cells that have different number of chromosomes as compared to the other cells have been reproductive cells. Thus, option D is correct.
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the burning of fossil fuels produces what kind of energy
Answer:
When fossil fuels are burned carbon and hydrogen react with oxygen in air to carbon dioxide (CO2) and water (H2O). During this reaction heat is released which further amplifies the reaction. Electricity is generated by transforming mechanical energy (heat) to electrical energy in a turbine or generator.
Explanation:
why dont fish fly bcs they have tiny wings
Answer:
okay....
Explanation:
technically, fish do not have wings. they are called fins and they are used for the purpose of transportation, just as legs are for humans.
~Ren
Can anyone help me with my homework
The exclusion zone restricts access to the area around Chernobyl. The soil is still radioactively contaminated after the Chernobyl nuclear explosion. Chernobyl had four nuclear reactors. Uranium dioxide, UO2, was the fuel in the reactors in Chernobyl.
Control rods slow chemical reactions because they absorb neutrons. This prevents the neutrons from reacting with additional uranium Protons and neutrons are found in the nucleus of an atom.
Isotopes are atoms of the same element that have the same number of protons and electrons but different numbers of neutrons. Iodine -131 half-life of eight days, strontium – 90 half-life of 29 years, cesium-137 half-life of 30 years In fission, the nucleus of a Uranium dioxide U-235 atom is bombarded by a neutron.
This splits the nucleus to release a daughter nuclei, more neutrons, and energy. If we start with a 30 g sample of Uranium dioxide I-131, there would be 7.5 grams of I-131.be after 16 days When one atom of uranium goes through fission, the reaction releases a small amount of energy. When the reaction is repeated on the mole scale though, the self-sustaining reaction becomes significantly larger, producing exponentially more energy.
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HELP if water vapor condense on a cold surface is the initial and final energy thermal, phase, or chemical?
Based on the proteins that were found in runners 2 cells, what can u say about his genes ?
Answer:runner has a1 and a2 it is heterozygous because it is two different gene verions.
Explanation:
the mass of the empty graduated cylinder is 35.101 g. if 12.33 g of water is added to this cylinder, what is the total mass?
The total mass of the cylinder and the water is 47.431g.
How to calculate mass?According to this question, the mass of an empty graduated cylinder is 35.101 g.
A graduated cylinder is known to be an item of glass laboratory equipment consisting of a tall, narrow cylinder with a scale, or graduations marked up its length, which is used to measure liquids and solutions fairly accurately, but not precisely.
If 12.33 g of water is added to this cylinder, the total mass of the cylinder and the water that was added can be calculated as follows:
Total mass = 12.33g (water) + 35.101g (empty cylinder) = 47.431g
Therefore, the total mass of the cylinder and the water is 47.431g.
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Please help me I need these answers
1 is true
2 is d 7
3 is
1 e
2 b
3 d
4 a
5 c
Part A
According to the following balanced reaction, how many moles of Ca(OH)2 will be formed from 4.33 moles of H₂O?
The number of moles of Ca(OH)2 formed is 4.33 moles.
Given,
number of moles of H₂O = 4.33
The balanced equation is :
CaO + H₂0 → Ca(OH)₂
From the balanced chemical reaction, we conclude that,
As 1 moles of H₂O react with 1 mole of Ca(OH)₂
Then, 4.33 moles of H₂O will react with 4.33 moles of H₂O.
Thus, the number of moles of Ca(OH)₂ formed will be 4.33 moles.
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Can someone explain how to do this?
Balanced equation :
3H₂+N₂⇒2NH₃
Further explanationEqualization of chemical reaction equations can be done using variables. Steps in equalizing the reaction equation:
1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c etc.
2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index between reactant and product
3. Select the coefficient of the substance with the most complex chemical formula equal to 1
Unbalanced⇒the number of atoms from both sides (reactants and products) is not the same
H₂+N₂⇒NH₃
H=2(left), H=3(right)
N=2(left), N=1(right)
Balanced ⇒ the number of atoms from both sides (reactants and products) is equal
3H₂+N₂⇒2NH₃
H=3x2=6(left), H=2x3=6(right)
N=2(left), N=2x1=2(right)
I need these done please
Answer:
A, it is metal oxide
30) Which of the following two atoms are isotopes?
Answer:
The correct is the letter B