In a flame test electrons are excited to higher energy levels and their emissions are observed. Therefore, option A is correct.
What is flame test ?The flame test is used to visually identify the identity of an unknown metal or metalloid ion based on the properties color the salt turns in the flame of a bunsen burner.
The color of light emitted depends on the energy emitted by an electron returning to its original state.
The flame's heat converts metal ions into atoms, which become excited and emit visible light. In a flame test electrons are excited to higher energy levels and their emissions are observed.
Thus, option A is correct.
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Please help me ASAP I’ll mark Brainly
Answer:
cell
chloroplast and cell wall
nucleus
life processes
cell membrane
shape and size
vacuole
Hope it helps
A cylinder contains 26.5 L of oxygen gas at a pressure of 1.7 atm and a temperature of 280 K. How much gas (in moles) is in the cylinder?
Answer:
The appropriate answer is "1.96 mol".
Explanation:
The given values are:
Volume,
V = 26.5 L
Pressure,
P = 1.7 atm
Temperature,
T = 280 K
Now,
The number of moles (n) will be:
= [tex]\frac{PV}{RT}[/tex]
By substituting the values, we get
= [tex]\frac{1.7\times 26.5}{0.0821\times 280}[/tex]
= [tex]\frac{45.05}{22.988}[/tex]
= [tex]1.96 \ mol[/tex]
In order for a substitution reaction to take place, at a minimum, __________ and ___________ are needed. carbocation rearrangement proton transfer loss of a leaving group nucleophilic attack
Answer: In order for a substitution reaction to take place, at a minimum, loss of a leaving group and nucleophilic attack are needed.
Explanation:
When one group in a molecule is replaced by another one then it is called a substitution reaction.
For a substitution reaction reaction to occur at a minimum, it is necessary to have a leaving group that helps in creating a carbocation and hence a nucleophile can easily attack.
For example, [tex]CH_{4} + Cl_{2} + h\nu \rightarrow CH_{3}Cl + HCl[/tex]
Thus, we can conclude that in order for a substitution reaction to take place, at a minimum, loss of a leaving group and nucleophilic attack are needed.
A 1.5-m 3 insulated rigid tank contains 2.7 kg of carbon dioxide at 100 kPa. Now paddle-wheel work is done on the system until the pressure in the tank rises to 150 kPa. Determine the entropy change of carbon dioxide during this process. Assume constant specific heats
Answer:
The entropy change of carbon dioxide = 0.719 kJ/k
Explanation:
Given:
1.5 m - 3 insulated rigid tank contains 2.7 kg of carbon dioxide at 100 kPa
The objective is to determine the entropy change of carbon dioxide
Formula used:
ΔS=
Solution:
On considering,
[tex]C_{P} =0.846 kJ/kg K\\C_V=0.657 kJ/kg k\\[/tex]
ΔS=[tex]mc_{v} lu\frac{p_{2} }{P_{1} }[/tex]
On substituting the values,
ΔS=[tex]2.7*0.657lu\frac{150}{100}[/tex]
ΔS=0.719 kJ/k
The entropy change is "0.719 kJ/K".
Given values are:
Mass of tank,
m = 2.7 kgPressure,
P₁ = 100 kPaRised pressure,
P₂ = 150 kPaAssumption of constant specific heat is,
[tex]C_v = 0.657 \ kJ/kgK[/tex]As we know the formula,
→ [tex]\Delta S = mC_v \ ln(\frac{P_2}{P_1} )[/tex]
[tex]= (2.7)(0.657) \ ln (\frac{150}{100} )[/tex]
[tex]= 1.7739\times 0.4055[/tex]
[tex]= 0.7193 \ kJ/K[/tex]
Thus above answer is right.
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The addition of chromic acid or chromate is a qualitative test for alcohols as the reaction causes a color change. However, not all alcohols react with chromic acid or chromate. Determine whether the named alcohol will react with chromic acid or chromate to cause a color change.
a. 3-hexanol
b. 1 -butanol
c. 2-pentanol
d. 3-ethyl-3-pentanol
Answer:
3-hexanol
1 -butanol
2-pentanol
Explanation:
Let us recall that chromic acid or chromate are strong oxidizing agents. When they are oxidized, their colour changes from orange to green.
This shows a reduction in chromic acid or chromate. The reaction of chromic acid or chromate with a primary alcohol yields a carboxylic acid while reaction with a secondary substrate yields an alkanal.
Note that Tertiary alkyl halides are not be oxidized hence reactions involving a point where invitation carried along occur.
3-ethyl-3-pentanol is a tertiary alkyl halide hence it can not be oxidized.
What is the volume of a gas 622.7 mL at 25.1 C if the temperature is increased to 60.7 C without changing the pressure, what is the new volume of the gas?
A. 697
B. 556
C. 1510
D. 9.35
Answer:
A) 697 mL
Explanation:
First convert degrees Celsius to Kelvin.
That gives;
For T1; temp 1 (273 + 25.1)
= 298.1K
T2; temp 2 (273+60.7)
=333.7K
From the formula, (V1/T1) = (V2/T2)
To find V2 = (V1/T1) × T2
= (622.7/298.1) × 333.7.
= 697.06mL
~~ 697mL
The rate law for the following reaction: H2SiF6(aq)+2NaF(aq)+3H2O(aq)⟶Na2SiO3(s)+8HF(aq) is second order in H2SiF6, zero order in NaF and first order in H2O. By what factor will the reaction rate change if the concentrations of all reactants are tripled?
Answer:
The rate law for the following reaction:
H2SiF6(aq)+2NaF(aq)+3H2O(aq)⟶Na2SiO3(s)+8HF(aq)
is second order in H2SiF6, zero order in NaF and first order in H2O.
Write the balanced dissociation equation for solid sulfur difluoride in aqueous solution. If it does not dissociate, simply write only NR.
Answer:
SF2(aq) → S²⁺(aq) + 2F-(aq)
Explanation:
The sulfur difluoride, SF2, dissolves in water because the differences in electronegativities are considerable (3.98 for Fluorine and 2.58 for S) doing the F-S bond polar. As water is a polar solvent will dissolve the SF2 as follows:
SF2(aq) → S²⁺(aq) + 2F-(aq)As Fluorine has a > electronegativity than S, the Fluorine will be negative and S will be positive. Also, all halogen ions has a charge of -1.
A chemistry student needs 90.0mL of carbon tetrachloride for an experiment. By consulting the CRC Handbook of Chemistry and Physics, the student discovers that the density of carbon tetrachloride is 1.59g*cm3- Calculate the mass of carbon tetrachloride the student should weigh out. Be sure your answer has the correct number of significant digits.
Answer:
volume = mass/density
Here, volume = 80g/1.59gcm-3 → 50.314 cm3
Explanation:
The number of mol of oxygen in 2.5 mol of caffeine
Answer:
5.0molO
Explanation:
To find the moles of oxygen in 2.5 moles of caffeine, we will first research caffeine's molecular formula: C8H10N4O2. From the molecular formula, we can see there are 2 oxygen atoms in every 1 molecule of C8H10N4O2.We can therefore multiply by the following mole ratio to get the moles of oxygen.
2.5molC8H10N4O2×2molO/1molC8H10N4O2 = 5.0molO.
A scientist is conducting a Sanger's sequencing experiment to determine the number of polypeptides present in an oligomeric protein. The molecular weight of the protein is 18000 g/mol . After the reaction of 520 mg of the protein with 1‑fluoro‑2,4‑dinitrobenzene, the peptide bonds were hydrolyzed with an acid. As a result, the scientist obtained 39 mg of 2,4‑dinitrophenyl serine. What is the number of the polypeptide chains present in the oligomer?
Answer:
Depends on molecule.
Explanation:
The number of the polypeptide chains present in the oligomer depends on the molecule. Some molecules have more polypeptide chains whereas some of them have less polypeptide chains. For example, Hemoglobin is a oligomer that consists of four Polypeptide Chains, two of these Polypeptide Chains are α-globin molecules, each comprise of 141 amino acids, and the other two are (β, γ, δ, or ε) globins, each consist of 146 amino acids.
A balloon contains 0.118 mol of gas and has a volume of 2.58 L . If an additional 0.116 mol of gas is added to the balloon (at the same temperature and pressure), what will its final volume be? Can you also show the work so I can understand why is it that answer. thank you
Answer:
v2=5.11L
Explanation:
given
v1=2.58L
N1=0.118mol
N2=0.234
v2=x
according to charles law V1/N1=V2/N2
2.58/0.118=V2/0.234
21.86=V2/0.234
21.86×0.234= v2
5.116L=v2
5.116L is the
answer or u can simplify it and make 5.1 L
How many moles of carbon dioxide at STP will fit in a 50 liter container?
Answer:
n = 2.23 moles
Explanation:
Given the following data;
Standard temperature = 273 K
Standard pressure = 101.325 kPa
Volume = 50 liter
R = 8.314 J/mol·K
To find the number of moles, we would use the ideal gas law formula;
PV = nRT
Where;
P is the pressure.V is the volume.n is the number of moles of substance.R is the ideal gas constant.T is the temperature.Making n the subject of formula, we have;
[tex] n = \frac {PV}{RT} [/tex]
Substituting into the formula, we have;
[tex] n = \frac {101.325*50}{8.314*273} [/tex]
[tex] n = \frac {5066.25}{2269.722} [/tex]
n = 2.23 moles
Therefore, 2.23 moles of carbon dioxide at STP will fit in a 50 liter container.
Classify each of the following as either macroscopic, microscopic or particulate:
a. a red blood cell.
b. a sugar molecule.
c. baking powder.
Answer:
Classify each of the following as either macroscopic, microscopic or particulate:
a. a red blood cell.
b. a sugar molecule.
c. baking powder.
Explanation:
a. A red blood cell is a microscopic particle.
It can be viewed under a microscope.
b. A sugar molecule is also a microscopic substance.
It can be viewed under a microscope.
c. Baking powder is macroscopic substance.
Suppose you analyze a 30.3 g sample of bleach and determine that there are 2.61 g of sodium hypochlorite present. What is the percent of sodium hypochlorite in the bleach sample
Answer:
8.61 %
Explanation:
The percent of sodium hypochlorite in the bleach sample can be calculated using the following formula:
% of sodium hypochlorite = Mass of sodium hypochlorite / mass of sample * 100%We input the data given by the problem:
% of sodium hypochlorite = 2.61 g / 30.3 g * 100 % = 8.61 %Suppose of potassium acetate is dissolved in of a aqueous solution of ammonium sulfate. Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the potassium acetate is dissolved in it. Round your answer to significant digits.
The question is incomplete, the complete question is;
Suppose 0.377g of potassium acetate is dissolved in 250.mL of a 57.0mM aqueous solution of ammonium sulfate.
Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the potassium acetate is dissolved in it.
Round your answer to 3 significant digits.
Answer:
0.0152 M
Explanation:
The equation of the reaction is;
2CH3COOK(aq) + (NH4)2SO4(aq)------> K2SO4(aq) + 2CH3COONH4(aq)
Number of moles of potassium acetate = 0.377g/98.15 g/mol = 0.0038 moles
Number of moles of ammonium sulphate = 250/1000L × 57 × 10^-3 = 0.014 moles
2 moles of potassium acetate yields 2 moles of ammonium acetate
Hence;
0.0038 moles of potassium acetate yields 0.0038 moles of ammonium acetate
Also
1 mole of potassium sulphate yields 2 moles of ammonium acetate
0.014 of potassium sulphate yields 0.014 × 2/1 = 0.028 moles of ammonium acetate
So potassium acetate is the limiting reactant.
Since 0.0038 moles of ammonium acetate is produced, the final concentration of potassium acetate is = 0.0038 moles of ammonium acetate/0.25L = 0.0152 M
Hence final concentration of acetate ions =0.0152 M
What does the term spontaneous mean in chemical reactions?
A. Producing heat as a product
B. Occurring without added energy
C. Occurring only at high temperatures
D. Occurring in an aqueous solution
Answer:
B
Explanation:
Spontaneous in chemical reactions means without any external input.
Occurring without added energy. Hence, option B is correct.
What is a spontaneous reaction?A spontaneous reaction is a reaction that supports the formation of products under the conditions under which the reaction is happening.
Spontaneous Reaction- a reaction that favours the formation of products at the conditions under which the reaction is occurring.
A non-spontaneous reaction can be made spontaneous if it is inside a controlled environment, this is what happens in nuclear power plants that create atomic fusion and fission in chambers that are controlled to control different particles to create nuclear active rays.
Hence, option B is correct.
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What type of a liquid will have a pH value equal to 12? (1 point)
Basic
Neutral
Strong acid
Weak aci
Answer: it will be basic
pH that ranges from 0-6 are acid
pH of EXACTLY 7 is neutral
pH greater than 7 are strongly basic or base
What is Heisnberg's uncertainity principle? Why it make sense only for microscopic particles.
Answer:
The uncertainty principle is one of the most famous (and probably misunderstood) ideas in physics. It tells us that there is a fuzziness in nature, a fundamental limit to what we can know about the behavior of quantum particles and, therefore, the smallest scales of nature.
One of the students in lab decided to use two fractionating columns (one on top of the other) instead of just one. How would this:_________.
a) affect the separation between hexane and heptane?
b) affect the yield of recovered pure hexane?
c) affect the yield of recovered pure heptane.
Explain your reasoning.
Answer:
See detailed explanation.
Explanation:
Hello there!
In this case, according to the given description, it turns out possible for us to infer that the second fractionating column on top of the first one will favor the light product, in this case hexane as it has the lowest boiling point and molar mass; in such a way, we can tell the following:
a) The separation between hexane and heptane will be increased as a purer hexane-rich product will be obtained on the top of the second column.
b) Will be increased as well, because the second column will remove more heptane.
c) Also, more pure heptane will be obtained on the bottom of the two columns, yet the most favored yield will be that of hexane.
All of the aforementioned is possible due to the fact that the second column will remove the amount of heptane that could not be removed on the top of the first column by taking the vapor-liquid equilibrium further from the first column's maximum separation, which is known as distillation sequences.
Regards!
What is the amount of solute required if the solution is 50 ml and the solvent is 35 ml. Solve and explain
I don’t know what to do
Answer:
15 mL of the solute
Explanation:
From the question given above, the following data were obtained:
Solution = 50 mL
Solvent = 35 mL
Solute =?
Solution is simply defined as:
Solution = solute + solvent
With the above formula, we can easily obtain the solute in the solution as follow:
Solution = 50 mL
Solvent = 35 mL
Solute =?
Solution = solute + solvent.
50 = solute + 35
Collect like terms
50 – 35 = solute
15 = solute
Solute = 15 mL
Therefore, 15 mL of the solute is required.
The Hammond Postulate describes the relationship between the energy of the transition state and the productdistribution in a reaction that is capable of following more than one pathway.
What are the appropriate labels for the sentence?
The Hammond postulate states that reactions which are thermodynamically endothermic and kinetically ___________ have transitions states that occur ___________ in the reacton time frame, and resemble the ___________ in terms of energy and structure.
¿soy guapo?
si dices que si te doy una galletita
Answer:
Hindi ko po ma gets sinasabi nyu pwedeng pakiayus
Consider equimolar samples of different ideal gases at the same volume and temperature. Gas A has a higher molar mass than gas B.
1. Compare the pressure
a. A > B
b. A= B
c. A < B
2. Compare the speed.
a. A > B
b. A= B
c. A < B
Answer:
I don't understand the question
Explanation:
1. c
2. c
Answer:
1. b. A = B
2. c. A < B
Explanation:
Consider equimolar samples of different ideal gases at the same volume and temperature. (nA = nB)
Gas A has a higher molar mass than gas B. (MA > MB)
1. We can calculate the pressure using the ideal gas equation.
P = n × R × T / V
Since n, T and V are equal, the pressure of both gases are equal as well.
2. We can calculate the root-mean-square of the velocity using the following expression.
v(rms) = √(3RT/M)
There is an inverse relationship between speed and molar mass. Since A has a higher molar mass, it has a lower speed.
Consider the arrangement of gases shown below. If the value between the gases is opened and the temperature is held constant, determine the following.
Answer:
I don't know what to say . just for points
The density of aluminum is 2.7 g/cm3.
Part A
What is its density in kilograms per cubic meter?
Express your answer in kilograms per cubic meter to two significant figures.
Answer:
2700 kg/m³
Explanation:
First let's convert 2.7 g/cm³ to kg/cm³, keeping in mind that 1 kilogram equals 1000 grams:
2.7 g/cm³ * [tex]\frac{1kg}{1000g}[/tex] = 0.0027 kg/cm³Finally we need to convert 0.0027 kg/cm³ to kg/m³, keeping in mind that 1 meter equals 100 centimeters, as follows:
0.0027 kg/cm³ * [tex](\frac{100cm}{1m} )^3[/tex] = 2700 kg/m³The answer is 2700 kg/m³.
20.1 cm3 of metal hydroxide (MOH) containing 4.8 g/dm3 react Completely with 23.0 cm3 of the HCL and Containing 3.8g/dm3. Identify the metal of M of MOH
Answer:
A metal M readily forms water-soluble sulphate MSO4, water-insoluble hydroxide M(OH)2 and oxide MO. The oxide and hydroxide are soluble in NaOH. The M is:
A Bronsted-Lowry acid is defined as a substance that ________. A Bronsted-Lowry acid is defined as a substance that ________. increases Ka when placed in H2O increases [OH-] when placed in H2O acts as a proton donor acts as a proton acceptor decreases [H ] when placed in H2O
Answer: A Bronsted-Lowry acid is defined as a substance that acts as a proton donor.
Explanation:
A substance that is able to donate a proton or hydrogen ion to another substance is a Bronsted-Lowry acid.
For example, HCl is a Bronsted-Lowry acid as it dissociates to give a hydrogen ion.
[tex]HCl \rightleftharpoons H^{+} + Cl^{-}[/tex]
Thus, we can conclude that a Bronsted-Lowry acid is defined as a substance that acts as a proton donor.
Determine whether each of the properties described applies to volumetric or graduated glassware. 1. Used for applications in which great accuracy is needed_____.a. volumetricb. graduated 2. Capable of measuring a range of volumes of liquid_____.a. volumetric
b. graduated 3. Designed to measure one specific volume of liquid_____.a. volumetric
b. graduated
Answer:
1) volumetric
2) graduated
3) volumetric
Explanation:
A volumetric glassware is a glassware that is marked at a particular point. A typical example of a volumetric glassware is the volumetric flask. A volumetric glassware is capable of measuring only a specific volume of a liquid.
On the other hand, graduated glassware can measure a range of volumes of liquid. However, a volumetric glassware is still required where a high degree of accuracy is important.
According to Newton's law of universal gravitation, how do the masses of two
objects relate to the gravitational force between them?
A. As either mass increases, the gravitational force between them
increases.
B. As either mass increases, the gravitational force between them
decreases.
C. Gravitational force increases only when both masses increase.
D. Gravitational force increases only when both masses decrease.
Answer:
As either mass increases, the gravitational force between them
increases.
Explanation:
According to Newton's law of universal gravitation;
F α m1m2/r^2
That is, the force between two masses in a gravitational field is directly proportional to the product of the two masses and inversely proportional to their distance apart.
Hence, as either of the masses increase, the force of gravitation between the two masses increases. Hence the answer.
