Answer:
positron emission
Explanation:
Positron emission,involves the decrease in the nuclear positive charge thus the atomic number of the daughter nucleus decreases by one unit compared to that of the parent nucleus while the mass number of the daughter nucleus remains the same as that of the parent nucleus.
Thus, when phosphorus-28 is transformed into to silicon-28, a positron emission has taken place because the mass number of the daughter nucleus remained the same while the atomic number of the daughter nucleus was decreased by one unit.
You have run an experiment studying the effects of the molecular weight of a compound on the rate of diffusion in agar. Compound X has a molecular weight of 25.3 g/mol and compound Y has a molecular mass of 156.2 g/mol. On two separate agar plates, 0.1 g of each substance were transferred and allowed to diffuse for 2 hours. The results below were obtained. Use this information about this situation to answer the following three questions.
a. What was the independent variable in this experiment?
b. What was the independent variable in this experiment?
c. List two controls that were held constant for this experiment or that you would hold constant for this experiment
Answer:
A) Molecular weight
B) Rate of diffusion
C) Agar plates
Time of diffusion
Explanation:
A) The independent variable is the molecular weight because it is the variable that the researcher changes at will to aid his research. It doesn't depend on other variables.
B) The dependent variable is "Rate of diffusion because it depends on the molecular weight of the compound.
C) A control variable is one that would be held constant throughout the research.
In this case, the agar plates and the time of 2 hours diffusion remain the same throughout.
How many moles of CO2 exert a pressure of 2.34atm at a volume of 25.6L and a temperature of 305k?
Answer:
2.39 moles
Explanation:
From the question given above, the following data were obtained:
Pressure (P) = 2.34 atm
Volume (V) = 25.6 L
Temperature (T) = 305 K
Number of mole (n) =?
NOTE: Gas constant (R) = 0.0821 atm.L/Kmol
The number of mole of CO₂ can be obtained by using the ideal gas equation as shown below:
PV = nRT
2.34 × 25.6 = n × 0.0821 × 305
59.904 = n × 25.0405
Divide both side by 25.0405
n = 59.904 / 25.0405
n = 2.39 moles
Thus, the number of mole of CO₂ is 2.39 moles.
Answer:
2.39
Explanation:
got it right on a quiz for credit recovery
1. When the following oxidation-reduction reaction in acidic solution is balanced, what is the
lowest whole-number coefficient for Rb*(aq)?
Rb(s) + Sr?+(aq) → Rb+ (aq) + Sr(s)
Answer:
2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)
Explanation:
Rubidium has a more negative reduction potential (-2.98 V) compared to strontium (-2.89 V).
Hence, in a redox reaction involving rubidium and strontium, rubidium will be oxidized while strontium is reduced.
The balanced redox reaction equation is obtained from;
Oxidation half equation;
2Rb(s) ---->2Rb^+(aq) + 2e
Reduction half equation;
Sr^2+(aq) + 2e ----> Sr(s)
Overall reaction equation;
2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)
identify the two functional groups in the following compound
Answer:
D. amine and alcohol
Explanation:
Organic compounds are identified using the functional group they contain. The functional group defines their peculiarity and chemical identity. For example, alkenes are identified by a double bond functional group (=), alcohols are identified by an hydroxyl functional group (OH) etc.
According to this question, a compound was given as an attached image. The compound posseses:
- an hydroxyl group (OH) indicating that it has an ALCOHOL functional group
- an N-H group indicating that it has an amine functional group
Spell out the full name of the compound.
Submit
Help plz
Explanation:
A=Butan-2-one
B=Pentan-3-one
Calculate the energy in kj/mol of photon in red light of wavelength 656nm
Answer:
you don't know the answer?ha me too
Concentration data is commonly monitored during a reaction to determine the order with respect to a reactant. Consider the types of observations listed, and determine which order is likely for that reactant. Assume all other factors are held constant. The reaction rate increases in direct proportion to the concentration of the reactant in solution.
a. The reaction rate is constant regardless of the amount of reactant in solution.
b. An increase in the concentration of the reactant in solution causes the reaction rate to increase exponentially.
Answer:
The reaction rate increases in direct proportion to the concentration of the reactant in solution - second order reaction
The reaction rate is constant regardless of the amount of reactant in solution - zero order reaction
An increase in the concentration of the reactant in solution causes the reaction rate to increase exponentially - first order reaction
Explanation:
In a second order reaction, the rate of reaction is directly proportional to the concentration of reactants. This implies that, reaction rate varies as the concentration of the reactant in solution varies.
For a zero order reaction, the rate of reaction is independent of the concentration of the reactants in solution. This means that reaction rate is constant regardless of the amount of reactant in solution.
For a first order reaction, the rate of reaction varies exponentially as the concentration of reactants. Hence, an increase or decrease in the concentration of the reactant in solution causes the reaction rate to increase or decrease exponentially.
Define solubility. a solid that does not dissolve in a gas the amount of a substance that will dissolve in a given amount of solvent the amount of a substance that will dissolve in a given amount of solute a liquid that does not dissolve in another liquid a solid mixed with another solid
Answer:
the amount of a substance that will dissolve in a given amount of solvent.
Explanation:
Solubility is a term used to describe how readily a substance can be dissolved in a solvent to form a solution. Thus, a substance is said to be soluble if it dissolves completely in a solvent and insoluble if it doesn't dissolve or only dissolves partially.
For example, sodium chloride (NaCl) when mixed with water dissociates into sodium and chloride ions. Thus, salt (sodium chloride) is said to be soluble because it dissolves completely in water.
Furthermore, a compound that dissolves completely in water to produce an aqueous solution is said to be soluble in water.
In conclusion, solubility is simply the amount of a substance such as salt, that will dissolve in a given amount of solvent. A solvent is any liquid such as water, coffee, tea, etc., that dissolves a liquid, gaseous, or solid solute to produce a solution.
What are the main modifications of John Dalton's atomic theory
In Denver, Colorado the elevation is about 5,280 feet above sea level. Explain what potential effects this may have on the solubility of a gaseous solute in a liquid solution.
Answer:
The solubility of the gaseous solute decreases
Explanation:
As we know, pressure decreases with altitude. This means that, at higher altitudes, the pressure is much lower than it is at sea level.
The solubility of a gas increases with increase in pressure and decreases with decrease in pressure.
Hence, in Denver, Colorado where the elevation is about 5,280 feet above sea level, a gaseous solute is less soluble than it is at sea level due to the lower pressure at such high altitude.
Phosphorus pentachloride, PCl5, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl5.
Answer:
0.186 moles
Explanation:
In order to convert grams of PCl₅ into moles, we need to use its molar mass:
Molar Mass of PCl₅ = Molar mass of P + (Molar mass of Cl)*5Molar Mass of PCl₅ = 208.24 g/molThen we proceed to calculate the number of moles:
38.7 g ÷ 208.24 g/mol = 0.186 molThere are 0.186 moles of PCl₅ in 38.7 g of PCl₅.In the given question Phosphorus pentachloride is used as a catalyst for certain chemical reaction. 38.7 g of [tex]\rm PCl_5[/tex], there are 0.186 moles of [tex]\rm PCl_5[/tex].
A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy required for the reaction to occur.
To calculate the number of moles in 38.7 g of [tex]\rm PCl_5[/tex], we need to divide the given mass of [tex]\rm PCl_5[/tex] by its molar mass.
The molar mass of [tex]\rm PCl_5[/tex] can be calculated by adding the atomic masses of one phosphorus atom and five chlorine atoms:
Molar mass of [tex]\rm PCl_5[/tex] = (1 x atomic mass of P) + (5 x atomic mass of Cl)
= (1 x 30.97 g/mol) + (5 x 35.45 g/mol)
= 208.22 g/mol
Now, we can calculate the number of moles of [tex]\rm PCl_5[/tex]:
Number of moles = mass / molar mass
= 38.7 g / 208.22 g/mol
= 0.186 moles
Therefore, there are 0.186 moles of [tex]\rm PCl_5[/tex] in 38.7 g of [tex]\rm PCl_5[/tex].
Learn more about catalyst here:
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Match each term with the best description.
a. The electrode where oxidation occurs
b. A device that produces electricity
c. The connection between two half-cells
d. The electrode where reduction occurs
e. A device that consumes electricity
f. A device that utilizes redox reactions to either consume or produce electricity
1. Anode
2. Cathode
3. Electrolytic cell
4. Electrochemical
5. Galvanic cell
6. Salt bridge
Answer:
Match each term with the best description.
a. The electrode where oxidation occurs: Anode
b. A device that produces electricity: Galvanic cell
c. The connection between two half-cells: salt bridge
d. The electrode where reduction occurs: Cathode
e. A device that consumes electricity: Electrolytic cell
f. A device that utilizes redox reactions to either consume or produce electricity: Electrochemical cell.
Explanation:
a.The electrode where oxidation occurs is called the anode.
Oxidation is losing of electrons.
b. Galvanic cell produces electricity by using redox chemical reaction.
It is also called a voltaic cell or electrochemical cell.
c. The connection between two cells is called a salt bridge.
It will not allow the solutions to diffuse with each other.
It maintains electrical neutrality.
d. The electrode where reduction occurs: Cathode
Reduction means the gaining of electrons.
e. Electrolytic cell is the one that consumes electricity and then produces a chemical change.
f. A device that utilizes redox reactions to either consume or produce electricity: Electrochemical cell.
Potassium Chlorate decomposes according to the reaction below.
2KClO3(s) 2KCl(s) + 3O2(g)
A 4.35 g sample of KClO3 is heated and the O2 gas produced by the reaction is collected in an evacuated flask. What is the volume of the O2 gas if the pressure of the flask is 0.75 atm and the gas temperature is 27oC? R=0.0821 (L*atm)/(mol*K)
Answer:
1.75L
Explanation:
Reaction of decomposition is:
2KClO₃(s) → 2KCl(s) + 3O₂(g)
We determine moles of salt:
4.35 g . 1 mol /122.55 g = 0.0355 moles
Ratio is 2:3. 2 moles of salt can produce 3 moles of oxygen
Then, our 0.0355 moles of chlorate may produce (0.0355 . 3)/ 2 = 0.0532 moles.
We have determined, moles of gas and we have data of pressure and temperature. To find out the volume, we apply the Ideal Gases Law:
We convert T° from °C to K → 27°C + 273 = 300K
P . V = n . R . T
0.75 atm . V = 0.0532 mol . 0.0821 L.atm/mol.K . 300K
V = (0.0532 mol . 0.0821 L.atm/mol.K . 300K) / 0.75 atm
V = 1.75 Liters
what is the theoretical yield of Mg(s) + O2(g) → MgO(s)
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An article about half-lives describes a parent isotope. What is a parent isotope?
A. The isotope that forms from the radioactive decay of a less stable isotope.
B. The isotope that forms from the radioactive decay of a more stable isotope.
C. The isotope that undergoes radioactive decay to form a less stable isotope.
D. The isotope that undergoes radioactive decay to form a more stable isotope.
I think the answer is D.
Answer:
D. The isotope that undergoes radioactive decay to form a more stable isotope.
Explanation:
In radioactivity, isotopes of an unstable atom disintegrates/decays into more stable ones accompanied with the emissions of certain particles e.g alpha, gamma and beta particles.
In this process, the isotope of the atom that undergoes radioactive decay to form a more stable isotope is known as the PARENT ISOTOPE while the more stable isotope that arises from the decay is called the DAUGHTER ISOTOPE.
(238, 92) Uranium → (234,90) Thorium + (4,2) Helium
In the above reaction, Uranium is the parent isotope because it decays into a more stable isotope (Thorium).
Answer:
He's Right
Explanation:
i got it right
Chemistry Grade 11: Hi, I don't know what this is, please help?
CALCULATING % YIELD STEPS:
1.
2.
3.
4.
Answer:
1. Write the balanced chemical equation for the reaction
2. Identify all important information provided in the word problems or data table.
3. Solve for the theoretical yield of the reaction, following all the steps of a stoichiometry calculation organizer. Use two calculations if both reactants are provided.
4. Use the percent yield equation to calculate the percent yield of the reaction.
Explanation:
its comes right from the 5.06 lesson
Sodium azide, NaN3, the explosive compound found in automobile air bags, decomposes according to the following equation: 2NaN3(s)right arrow 2Na(s) + 3N2(g)
What mass of NaN3 is required to provide the nitrogen needed to inflate an 80.0-L bag to a pressure of 1.3 atm at 27 degree C? What is the density of the gas under these conditions?
Answer:
1.9 × 10² g NaN₃
1.5 g/L
Explanation:
Step 1: Write the balanced decomposition equation
2 NaN₃(s) ⇒ 2 Na(s) + 3 N₂(g)
Step 2: Calculate the moles of N₂ formed
N₂ occupies a 80.0 L bag at 1.3 atm and 27 °C (300 K). We will calculate the moles of N₂ using the ideal gas equation.
P × V = n × R × T
n = P × V / R × T
n = 1.3 atm × 80.0 L / (0.0821 atm.L/mol.K) × 300 K = 4.2 mol
We can also calculate the mass of nitrogen using the molar mass (M) 28.01 g/mol.
4.2 mol × 28.01 g/mol = 1.2 × 10² g
Step 3: Calculate the mass of NaN₃ needed to form 1.2 × 10² g of N₂
The mass ratio of NaN₃ to N₂ is 130.02:84.03.
1.2 × 10² g N₂ × 130.02 g NaN₃/84.03 g N₂ = 1.9 × 10² g NaN₃
Step 4: Calculate the density of N₂
We will use the following expression.
ρ = P × M / R × T
ρ = 1.3 atm × 28.01 g/mol / (0.0821 atm.L/mol.K) × 300 K = 1.5 g/L
10-Concentration is the amount of a substance in a predefined volume of space. The basic measurement of concentration in chemistry is molarity or the number of moles of solute per liter of solvent. What is the molarity of a solution containing 9.478 grams of Rucl, in enough water to make 1.00 L of solution?
Answer:
0.0457 M
Explanation:
Concentration is the amount of a substance in a predefined volume of space. The basic measurement of concentration in chemistry is molarity or the number of moles of solute per liter of solution. What is the molarity of a solution containing 9.478 grams of RuCl₃, in enough water to make 1.00 L of solution?
Step 1: Given data
Mass of RuCl₃ (solute): 9.478 gVolume of solution: 1.00 LStep 2: Calculate the moles corresponding to 9.478 g of RuCl₃
The molar mass of RuCl₃ is 207.4 g/mol.
9.478 g × 1 mol/207.4 g = 0.04570 mol
Step 3: Calculate the molarity of the solution
We will use the definition of molarity.
M = moles of solute / liters of solution
M = 0.04570 mol / 1.00 L = 0.0457 M
A 0.15 M solution of BaCl2 contains: Group of answer choices 0.30 M Ba2 ions and 0.30 M Cl- ions. 0.15 M Ba2 ions and 0.15 M Cl- ions. 0.30 M Ba2 ions and 0.15 M Cl- ions. 0.15 M Ba2 ions and 0.30 M Cl- ions. none of the above
Answer:
0.15 M Ba⁺² ions and 0.30 M Cl⁻ ions
Explanation:
The dissociaton of barium chloride is as follows:
BaCl₂ → Ba²⁺ + 2Cl⁻
By observing the stoichiometric coefficients, we can tell that the number of moles of Ba²⁺ is the same as the number of moles of BaCl₂, while the number of moles of Cl⁻ is the double of that.
What are the TWO characteristics of an effective collision?
Answer:
the TWO characteristics of an effective collision are:
1.Molecules collide with sufficient energy
2.Molecules collide with the proper orientation.
Calcular el pH de una disolución cuando 10 g de NaOH se diluyen con agua hasta un volumen final de 250 ml
Answer:
My nettttttworkkkk is slowww
What are the geometrical shape of BeCl2 and CO2?
Answer:Answer: BeCl2 And CO2 Both Molecules Have The Same - OOOOOOO Molecular Geometry (molecular Shape) Number Of Covalent Bonds To The Central Atom Total Number Of Each Type Of Bond (single, Double, Triple) Number Of Electron Pairs Around The Central Atom Electron Region Geometry (3-D Arrangement Of Electron Pair Regions
Explanation:
A 420 mL sample of a 0.100 M formate buffer, pH 3.75, is treated with 7 mL of 1.00 M KOH. What is the pH following this addition? (pKa for formic acid is 3.75)
Answer: The pH of the resulting solution will be 3.60
Explanation:
Molarity is calculated by using the equation:
[tex]\text{Molarity}=\frac{\text{Moles}}{\text{Volume}}[/tex] ......(1)
We are given:
Molarity of formic acid = 0.100 M
Molarity of potassium formate = 0.100 M
Volume of solution = 420 mL = 0.420 L (Conversion factor: 1 L = 1000 mL)
Putting values in equation 1, we get:
[tex]\text{Moles of formic acid}=(0.100mol/L\times 0.420L)=0.0420mol[/tex]
[tex]\text{Moles of potassium formate}=(0.100mol/L\times 0.420L)=0.042mol[/tex]
Molarity of KOH = 1.00 M
Volume of solution = 7 mL = 0.007 L
Putting values in equation 1, we get:
[tex]\text{Moles of KOH}=(1mol/L\times 0.007L)=0.007mol[/tex]
The chemical equation for the reaction of formic acid and KOH follows:
[tex]HCOOH+KOH\rightleftharpoons HCOOK+H_2O[/tex]
I: 0.042 0.007 0.042
C: -0.007 -0.007 +0.007
E: 0.035 - 0.049
Volume of solution = [420 + 7] = 427 mL = 0.427 L
To calculate the pH of the acidic buffer, the equation for Henderson-Hasselbalch is used:
[tex]pH=pK_a+ \log \frac{\text{[conjugate base]}}{\text{[acid]}}[/tex] .......(2)
Given values:
[tex][HCOOK]=\frac{0.049}{0.427}[/tex]
[tex][HCOOH]=\frac{0.035}{0.427}[/tex]
[tex]pK_a=3.75[/tex]
Putting values in equation 2, we get:
[tex]pH=3.75-\log \frac{(0.049/0.427)}{(0.035/0.427)}\\\\pH=3.75-0.146\\\\pH=3.60[/tex]
Hence, the pH of the resulting solution will be 3.60
Calculate the pressure exerted by 40 g of oxygen enclosed in a 1litre flask at 25°C. (0=16) (3 Marks)
Answer:
I don't know sorry siso
Explanation:
I don't know
Compound A and compound B are constitutional isomers with molecular formula C3H7Cl. When compound A is treated with sodium methoxide, a substitution reaction predominates. When compound B is treated with sodium methoxide, an elimination reaction predominates.
Required:
Propose structures A and B.
Answer:
Compound A and compound B are constitutional isomers with molecular formula C3H7Cl.
When compound A is treated with sodium methoxide, a substitution reaction predominates. When compound B is treated with sodium methoxide, an elimination reaction predominates.
Explanation:
Constitutional isomers are the one which differs in the structural formula.
When compound A is treated with sodium methoxide, a substitution reaction predominates.
That means sodium methoxide is a strong base and a strong nucleophile.
But when it reacts with primary alkyl halides it forms a substitution product and when it reacts with secondary alkyl halide it forms mostly elimination product.
The reaction and the structures of A and B are shown below:
g What happens to the intensity of the solution's color as the concentration of the solute changes? The intensity of the color directly changes in response to the concentration. The intensity of the color inversely changes in response to the concentration. The intensity of the color always increases in response to any concentration change. The intensity of the color always decreases in response to any concentration change. The intensity of the color does not change in response to any concentration change.
Answer:
The intensity of the color directly changes in response to the concentration
Explanation:
One of the major indicators of the concentration of a solution is the colour of the solution.
The colour of the solution changes as the concentration of the solution changes. If the solution becomes more concentrated, the colour of the solution becomes deeper. If the solution becomes more dilute, the colour of the solution becomes lighter.
It then follows that, the intensity of the color of a solution directly changes in response to the concentration of the solution.
2) If the density of chloroform is 1.48 g/mL, what is the volume of 541 g of chloroform?
Answer:
V = 365.54 mL
Explanation:
Given that,
The density of chloroform, d = 1.48 g/mL
The mass of chloroform, m = 541 g
We need to find the volume of chloroform.
We know that,
Density = mass/volume
So,
[tex]V=\dfrac{m}{d}\\\\V=\dfrac{541\ g}{1.48\ g/mL}\\\\=365.54\ mL[/tex]
So, the volume of chloroform is 365.54 mL.
Which of the following is NOT true about soil? *
n a combination redox reaction, two or more ____________ , at least one of which is a(n) ____________ , form a(n) ____________ . General Reaction: ____________ In a decomposition redox reaction, a(n) ____________ forms two or more ____________ , at least one of which is a(n) ____________ . General Reaction: ____________ In double-displacement (metathesis) reactions, such as precipitation and acid-base reactions, ____________ of two ____________ exchange places; these reactions ____________ redox processes.General Reaction: ____________ In solution, single-displacement reactions occur when a(n) ____________ of one ____________ displaces the ____________ of another. Since one of the ____________ is a(n) ____________ , a
Answer:
In a combination redox reaction, two or more reactants, at least one of which is a(n) element, form a(n) compound. General Reaction: X + Y > Z
In a decomposition redox reaction, a(n) compound forms two or more products, at least one of which is a(n) element. General Reaction: Z>X+Y
In double-displacement (metathesis) reactions, such as precipitation and acid-base reactions, atoms (or ions) of two compounds exchange places; these reactions are not redox processes. General Reaction: AB+CD>AD+CB
In solution, single-displacement reactions occur when a(n) atom of one element displaces the atom of another. Since one of the reactants is a(n) element, all single-displacement reactions are redox processes. General Reaction: X+YZ>XY+Z
Explanation:
In a combination redox reaction, two or more reactants, at least one of which is a(n) element, form a(n) compound.
General Reaction: X + Y > Z
In the reaction scheme above, X combines with Y to give Z as a product.
In a decomposition redox reaction, a(n) compound forms two or more products, at least one of which is a(n) element.
General Reaction: Z>X+Y
In the reaction scheme above, Z decomposes to X and Y
In double-displacement (metathesis) reactions, such as precipitation and acid-base reactions, atoms (or ions) of two compounds exchange places; these reactions are not redox processes since there are no changes occurring in the oxidation number of the atoms (or ions) involved.
General Reaction: AB+CD>AD+CB
In the reaction scheme above, B and D exchange places in their respective compounds
In solution, single-displacement reactions occur when a(n) atom of one element displaces the atom of another. This type of reaction is due to the difference in the reactivities of the elements. The more reactive atom of one element displaces the least reactive atom of another element from its solution.
Since one of the reactants is a(n) element, all single-displacement reactions are redox processes.
General Reaction: X+YZ>XY+Z
In the reaction scheme above, X displaces Z from the compound YZ.
