The mass of this isotope that is required to give an activity of 205 C is 1.187 mg.
What is isotope?Isotope is defined as two or more different types of atoms with the same atomic number, but different nucleon values at different positions on the periodic table. Isotopes are forms of an element that have the same number of protons and electrons but differing numbers of neutrons.
Let's first translate the 2.70 day half life into seconds to obtain the following half life:
T(1/2) = 233300 sec
By subtracting the half life from ln(2)? = 2.971x10⁻⁶, determine the decay constant.
Now that we have the decay constant, we can solve for the quantity of isotopes required to produce an activity of 290 Ci (which is equal to 1.073x10¹³ decays per second) using the rate of decay equation. Due to the fact that we are discussing the beginning action, t = 0 for this equation.
-1.073x10³ = -A?e^(-? x 0)
Since we are losing isotopes rather than acquiring them, the left side of the equation is negative.
Fill in the blanks: A = 3.611x10¹⁸ isotopes
Find out how much mass is contained in all of these isotopes now.
(3.611x10¹⁸) x(198u) = 7.150x10²⁰ u
To get the final result, convert to mg at this point:
1.187 mg
Thus, the mass of this isotope that is required to give an activity of 205 C is 1.187 mg.
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The moon appears red during a lunar eclipse because red is the __________ wavelength of light in the color spectrum present in sunlight.
longest
shortest
brightest
Answer:
Longest
Explanation:
The visible light spectrum goes from red color to blue color:
The red wavelength of light has the lowest energy in that spectrum, and as such, it is the longest wavelength.Conversely, the blue wavelength of light has the highest energy in that spectrum, and as such, it is the shortest wavelength.As it has the longest wavelength, it can travel further than other wavelengths, which is why the moon appears red during a lunar eclipse.
What is higher boiling point alkyne or alkyl halides??
Answer: alkyl halide
Explanation: brianlist please?
what is the difference between refference and indicator electrode
Answer:
The key difference between indicator electrode and reference electrode is that indicator electrode responds to changes in the activity of the analyte, whereas reference electrode does not respond to changes, and its response is stable.
Explanation:
Remember: all EM waves travel at the same __________. The equation for speed is __________ times the __________. So, for the answer to always be 300,000km/s, as one number goes __________, the other must go __________. All EM waves are __________. The higher the __________, the more __________ in the wave.
All the EM waves travel at the same speed. The equation for speed is frequency (v) times the wavelength (λ). Speed of light equals 300000 km/s. Hence one number goes to 3 × 10⁸ m and other number is 1 s⁻¹.
What is an electromagnetic wave ?Electromagnetic waves are waves moving without a medium through vacuum. They are accompanied with an electric field and magnetic field. The speed of an electromagnetic wave is the product its wavelength and frequency.
c = νλ
Therefore, the given passage can be filled as follows:
All the EM waves travel at the same speed. The equation for speed is frequency (v) times the wavelength (λ). Speed of light equals 300000 km/s. Hence one number goes to 3 × 10⁸ m and other number is 1 s⁻¹.
All EM waves are energetic. The higher the frequency the more energy in the wave.
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An analytical chemist is titrating 99.2 mL of a 0.6300 M solution of dimethylamine ((CH3 NH) with a 0.2500 M solution of HNO3. The p K, of dimethylamine is 3.27. Calculate the pH of the base solution after the chemist has added 213.6 mL of the HNO3 solution to it.
Answer:
pH of the base solution after the chemist has added 213.6 mL of the HNO3 solution to it is 9.96
Explanation:
Calculating the moles of dimethylamine
Moles of dimethylamine = molairty * volume in L = 0.63*0.0992 = 0.0625moles
Moles of HNO3 = molarity * volume in L = 0.25*0.2136 = 0.0534 moles
The balanced chemical equation is
(CH3)2NH + HNO3 -------------------> (CH3)2NH2^+ + NO3^-
I 0.0625 0.0534 0
C -0.0534 - 0.0534 0.0534
E 0.0091 0 0.0534
As we know ,
POH = Pkb + log[(CH3)2NH2^+]/[(CH3)2NH]
= 3.27 + log0.0534/0.0091
= 3.27+ 0.768
= 4.038
PH = 14-POH
= 14-4.038 = 9.96
a) S₂08²+ I- ----> I3- + SO₂ The reaction is carried out in a basic solution. Express a balanced redox equation using the ion-electron method.
Answer:
The ion-electron method involves breaking the reactants into their component ions and transferring electrons between the ions to balance the charge and the atoms. In a basic solution, the S²⁰⁸² ion will gain two electrons to form SO₂. The I¹⁻ ion will lose one electron to form I³⁻. The balanced redox equation using the ion-electron method is:
S²⁰⁸² + 2e⁻ + 2OH⁻ → SO₂ + H₂O
I¹⁻ + e⁻ → I³⁻
The overall balanced equation is:
2S²⁰⁸² + 2OH⁻ + I¹⁻ → 2I³⁻ + SO₂ + H₂O
Assign oxidation numbers to each atom in each substance. Then check your work by summoning to zero for each compound or the charge on the ion for the polyatomic. (Please help I am awful at chemistry )
The oxidation number of the atoms in the given compounds are :
K₂O: K = + 1; O = -2;
PO₃⁻³: P = +3; O = -2
NH₃: N = -3; H = +1
Cu(NO₃)₂: Cu = +2; N = +5; O = -2
NO₃⁻¹: N = +5; O = -2
CO₂: C = +4; O = -2
KClO₃: K = +1; Cl = + 5; O = -2
O₂: O = 0
Ca(ClO₄)₂: Ca = +2; Cl = +7; O = -2
What is the oxidation number of elements?The number of electrons an atom or ion has either gained or lost in comparison to the neutral atom is known as the oxidation number or state of the atom or ion.
Group I, 2, and 3 electropositive metal atoms lose a certain number of electrons, and their positive oxidation numbers remain constant.
The oxidation number of the atoms in the given compounds are as follows:
K₂0
K = + 1
O = -2
Sum is (+1 * 2) + (-2) = 0
PO₃⁻³
P = + 3
O = -2
Sum is (+3) + (-2 * 3) = -3
NH₃
N = -3
H = +1
Sum is (-3) + (+1 * 3) = 0
Cu(NO₃)₂
Cu = +2
N = +5
O = -2
Sum is (+2) + (+5 * 2) + (-2 * 6) = 0
NO₃⁻¹
N = +5
O = -2
Sum is (+5) + (-2 * 3) = -1
CO₂
C = +4
O = -2
Sum is (+4) + (-2 * 2) = 0
KClO₃
K = +1
Cl = + 5
O = -2
Sum is (+1) + (5) + (-2 * 3) = 0
O₂
O = 0
Sum is (0 * 2) = 0
Ca(ClO₄)₂
Ca = +2
Cl = +7
O = -2
Sum is (+2) + (+7 * 2) + (-2 * 8) = 0
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How can heat change matter from a solid to a liquid to a gas?
Help ima mark Brainlyest!!
When applying heat the solid will eventually reach its melting point. Its then that the solid will slowly start to turn into a liquid due to the heat transfer. The process will only continue with even more heat piling up causing it to evaporate and become a gas.
Heat transfer comes in different ways depending on the solid:
either-
| | |
conduction
convection
or
radiation
- - - - -
this is all I know for now.
-------------------------------------------
Lucky me! We actually learned this in class today
I hope I helped in some way! :)
1. Which of the following is a mechanical mixture?
A. shampoo
B. chocolate chip cookie dough
C. tap water
D. air
Calculate the molarity of the following solution: 1.0 mole of KCI in 750.0 mL of
solution.
99 M
0.750 M
B 2.0 M
1.3 M
1.3 mol ⋅ L − 1
Molarity=
Moles of solute/ Volume of solution
how does salinity differ in a river, estuary, and an ocean?
Answer:
Because fresh water flowing into the estuary is less salty and less dense than water from the ocean, it often floats on top of the heavier seawater. ... For example, a heavy spring rain, or a sustained shift in local winds, can drastically affect the salinity in different parts of an estuary.
Answer:
Because fresh water flowing into the estuary is less salty and less dense than water from the ocean, it often floats on top of the heavier seawater.For example, a heavy spring rain, or a sustained shift in local winds, can drastically affect the salinity in different parts of an estuaryHow many grams of Fe2O3 can be produced from 180 g Fe ?
Answer:
257.6 grams
Explanation:
first write the formula: 4Fe + 3O2 -> 2Fe2O3
Fe molar mass is 55.8
180/55.8 = 3.226 mols
devide 3.226 by 4, then multiply by 2 which gives us 1.61 mols Fe2O3
Fe2O3 molar mass is 160
1.61 mols * 160 = 257.6 grams
[H3O+] = 3.6 x 10-2 M
Answer:
om pH
The hydronium ion concentration can be found from the pH by the reverse of the mathematical operation employed to find the pH. [H3O+] = 10-pH or [H3O+] = antilog (- pH) Example: What is the hydronium ion concentration in a solution that has a pH of 8.34?
Explanation:
use the kinetic particle model to describe the motion and separation of the particles in solid carbon dioxide and carbon dioxide gas
In solid carbon dioxide (dry ice), the particles are held together by strong covalent bonds, so they do not move around much.
What is the carbon dioxide?
Carbon dioxide (CO2) is an odorless, colorless gas created through natural processes such as respiration, combustion and the breakdown of organic materials. As a greenhouse gas, it is a major component of the Earth’s atmosphere and plays a critical role in regulating the global climate. Carbon dioxide is made up of one carbon atom and two oxygen atoms, and is produced when fossil fuels such as coal and oil are burned. Plants and trees also use carbon dioxide as part of their photosynthesis process. Carbon dioxide is essential for life on Earth, however, too much of it can have a negative impact on our planet. As human activity has increased over the past century, so too has our production of CO2, resulting in higher concentrations of this gas in the atmosphere and contributing to global warming.
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"Calculate the pH of a 0.15 M NaOH solution AND classify the solution of acidic, neutral, and basic"
a. 0.82 basic
b.0.82 acidic
c. 13.2 basic
d. 13.2 acidic
Answer:
la respuesta es la letra a
The entropy change for a real, irreversible process is equal to:______.
a. the entropy change for a theoretical reversible process with the same initial and final states.
b. equal to the entropy change for the same process performed reversibly ONLY if the process can be reversed at all.
c. zero.
d. impossible to tell.
Answer:
The entropy change for a real, irreversible process is equal to zero.
The correct option is 'c'.
Explanation:
Lets look around all the given options -:
(a) the entropy change for a theoretical reversible process with the same initial and final states , since the entropy change is equal and opposite in reversible process , thus this option in not correct.
(b) equal to the entropy change for the same process performed reversibly ONLY if the process can be reversed at all. Since , the change is same as well as opposite too . Therefore , this statement is also not true .
(c) zero. This option is true because We generate more entropy in an irreversible process. Because no heat moves into or out of the surroundings during the procedure, the entropy change of the surroundings is zero.
(d) impossible to tell. This option is invalid , thus incorrect .
Hence , the correct option is 'c' that is zero.
Answer: the entropy change for a theoretical reversible process with the same initial and final states
The EM Spectrum is the __________ range of EM waves in order of __________ frequency and __________ wavelength.
Answer:
entire, increasing, decreasing
Explanation:
The EM Spectrum is the entire range of EM waves in order of increasing frequency and decreasing wavelength.
S + 6 HNO3 → H2SO4 + 6 NO2 + 2 H2O
In the above equation, how many grams of water can be made when 12.1 moles of HNO3 are consumed?
Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer as 4.0
Use the following molar masses. If you do not use these masses, the computer will mark your answer incorrect.:
Element Molar Mass
Hydrogen 1
Nitrogen 14
Sulfur 32
Oxygen 16
The amount, in grams, of water that can be made when 12.1 moles of [tex]HNO_3[/tex] are consumed would be 72.54 grams.
Stoichiometric problemFrom the balanced equation of the reaction, the mole ratio of [tex]HNO_3[/tex] to water is 3:1.
This means that for every 3 moles of [tex]HNO_3[/tex], 1 mole of water will be produced.
3 mole [tex]HNO_3[/tex] = 1 mole water
12.1 moles HNO3 = 12.1x1/3
= 4.03 mol
Recall that: mass = mole x molar mass
The molar mass of water is 18 g/mol
Thus, the mass of 4.03 mol of water = 4.03 x 18 = 72.54 grams
In other words, going by the equation of the reaction, the mass of water that can be made when 12.1 moles of [tex]HNO_3[/tex] are consumed would be 72.54 grams.
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Which term is a measurement of heat?
A. Hot
B. Warm
C. Cold
D. Temperature
Answer:
A? or maybe C?
Explanation:
Hot is heat... right? so is warm.. Am i missing something?
Answer:
The answer is D
Explanation:
I got it correct on the quiz.
QUESTION 62
Which of the following pH values represents the highest concentration of H30+ ions?
O pH 5.4
O pH 7.0
O pH 8.7
O All of the above have the same concentration of hydronium ions
O cannnot be determined with the given information
Answer:
5.4
Explanation:
The lower the pH the more H3o+ ions there are
Chemical changes are changes that involve a change in the chemical identity of a substance. In other words, a new chemical or substance is created through a chemical change. A chemical change is also thought of as a chemical reaction.
Required:
Write down some ecample of a chemical change.
Answer:
The chemical change is "Frying an egg".
Explanation:
As the thermal energy is present while cooking an egg, these same components of such an egg transform their appearances as well as their consistency probably forever.Throughout the process of denaturation, the above transformation process or strategy of such a fried egg can't be completely overturned.Thus the above is the right answer.
O
Question 2 of 10
Which of the following values best classifies a bond between 2 atoms as
being covalent?
A. An electronegativity difference of greater than 2.7 between the
atoms
B. An electronegativity difference of greater than 1.7 between the
atoms
C. An electronegativity difference of less than 1.7 between the atoms
D. An electronegativity difference of less than 2.7 between the atoms
← PREVIOUS
SUBMIT
A bond between 2 atoms as being covalent an electronegativity difference of greater than 1.7 between the atoms.
What is bond?Bond is a debt instrument, which is issued by governments and corporations. These bonds are used to raise capital for various projects and investments. Bonds are a form of loan and investors are usually paid a fixed interest rate for lending their money. Bonds are typically issued for a fixed period of time, usually for a period of 5-30 years, and have a fixed maturity date. Investors receive interest payments at regular intervals and receive the principal amount of the bond at the end of the period.
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Arrange the species according to the oxidation state of nitrogen in each. Note that highest refers to the most positive oxidation state of nitrogen, whereas lowest refers to the most negative oxidation state.
A. NO3-
B. NO4+
C. N2
D. NH2OH
E. NO2-
1. Highest oxidation state
2. Lowest oxidation state
Answer:
A. NO₃⁻ ⇒ +5
B. NO₄⁺ ⇒ +9
C. N₂ ⇒ 0
D. NH₂OH ⇒ -1
E. NO₂⁻ ⇒ +3
Explanation:
To calculate the oxidation number of an element in a compound, we have to know the oxidation number of the other elements. Then, we have to consider that the sum of the oxidation number of each atom multiplied by the subscripts is equal to the net charge of the compound.
A. NO₃⁻
This is the ion nitrate. Oxygen atoms (O) has an oxidation number of -2 because it derives from an oxide. In this case, the net charge of the ion is -1. Thus, we calculate the oxidation number of N as follows:
N + (3 x (-2)) = -1
N - 6 = -1 ⇒ N= -1 + 6 = +5
B. NO₄⁺
In this case, the sum of the oxidation numbers of O and N multiplied by the subscripts is equal to +1:
N + (4 x (-2)) = +1
N - 8 = +1 ⇒ N = +1 +8 = +9
C. N₂
The oxidation number of N is 0 because N₂ is an elemental substance.
D. NH₂OH
The oxidation number of H is +1 and -2 for O. The net charge of the molecule is 0.
N + (H x 3) + (O) = 0
N + (+1 x 3) + (-2) = 0
N + 3 -2 = 0 ⇒ N = 2 - 3 = -1
E. NO₂⁻
The net charge of the ion nitrite is -1.
N + (2 x O) = -1
N + (2 x (-2)) = -1 ⇒ N = -1 + 4 = +3
Therefore:
Highest oxidation number = B. NO₄⁺ (+9)
Lowest oxidation number = D. NH₂OH (-1)
how does a heavy growth of algae decrease the concentration of oxygen in a lake?
Answer:
Explanation:
iuhyesfdxgrygtvd ctrfdrdt6r76_jjdvrud83447+je8867vbde turn left then go right back then stop done
A chemist has one solution that is 30.% acid and another solution that is 18% acid. How much of each solution should be used to get 300. L of a solution that is 21% acid?
a. 23 L of the 30.% solution and 277 L of the 18% solution
b. 75 L of the 30.% solution and 225 L of the 18% solution
c. 131 L of the 30.% solution and 169 L of the 18% solution
d. 138 L of the 30.% solution and 162 L of the 18% solution
e. 244 L of the 30.% solution and 56 L of the 18% solution
There is a golden rule of solubility, non polar solute dissolve in non polar solvent and polar solute dissolve in polar solvent. Therefore, the correct option is option B.
What is solution?
Solution is a homogeneous mixture of two or more than two substances. A solution is a homogeneous mixture of solute and solvent molecules. Solvent is a substance that is in large amount in solution. solute is the substance which is in small amount in a solution.
There are two types of mixture that is homogeneous and heterogeneous. Solution is a homogeneous solution. The nature of solvent tells about whether the solvent is in liquid, solid or gas form.
Let amount of 30% to mix, be X
Then amount of 18% to mix = 300 - X
0.3X + 0.18(300 - X) = 0.21(300)
0.3X+ 0.18(300) - 0.18X= 0.21(300)
0.3X - 0.18X =0 .21(300) -0 .18(300)
0.12X =0 .03(300)
X=75L
Therefore, the correct option is option B.
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Which of the following is the balanced equation
for the decomposition of hydrogen peroxide
(H2O2) into water and oxygen gas?
A H2O2 - 2H + 20
В. НО
H202 -- H2O + O2
a
2H202
H2O + 202
D 2H202 - 2H2O + O2
Answer:
D
Explanation:
2H202 = 2H2O + O2
Please I need help with this question.
Answer:
c?
Explanation:
Answer:
b
Explanation:
What's the lewis structure of NO3- and O3?
I end up finding the apparently wrong ones for both, and am probably missing out on an important notion.
The lewis structure of NO₃⁻ is trigonal planar and the Lewis structure of ozone (O₃) has a resonance form.
What are Lewis structures?Lewis structures which are also often referred to as Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures, depict the interactions between the atoms in a molecule as well as any lone pairs of electrons that may be present.
NO₃⁻ has a trigonal planar Lewis structure. It has one nitrogen atom, three oxygen atoms, and covalent bonds holding the three oxygen atoms together. The sp² hybridization of the nitrogen atom gives NO₃⁻- its trigonal planar structure.
Three oxygen atoms make up the oxygen allotrope known as ozone (O₃). One double bond and one single bond make up the Lewis structure of ozone. Additionally, two oxygen atoms in the Lewis structure of O3 carry charges.
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I want to know how to solve this question by step by step.
Question: What is the pH value of 500ml of an aqueous solution of 0.005 mol HCl ?
The pH value of 500 mL of an aqueous solution of 0.005 mole HCl is 2
How do I determine the pH of the solution?We'll begin our calculations by obtaining the molarity of the solution. Details below:
Volume of solution = 500 mL = 500 / 1000 = 0.50 LMole of HCl = 0.005 moleMolarity = ?Molarity = mole / volume
Molarity = 0.005 / 0.50
Molarity = 0.01 M
Next, we shall obtain the concentration of the hydrogen ion, H⁺ in the solution. Details below:
HCl(aq) <=> H⁺(aq) + Cl¯(aq)
From the balanced equation above,
1 mole of HCl contains 1 mole of H⁺
Therefore,
0.01 M HCl will also contain 0.01 M H⁺
Thus, the concentration of the hydrogen ion, H⁺ in the solution is 0.01 M
Finally, we shall determine the pH of the solution. Details below:
Concentration of hydrogen ion [H⁺] = 0.01 MpH of solution =?pH = -Log H⁺
pH = -Log 0.01
pH = 2
Thus, we can conclude that the pH of the solution is 2
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Let us assume that Cd(OH)2(s) is completely insoluble, which signifies that the precipitation reaction with NaOH(aq) (presented in the transition) would go to completion.
Cd2+(aq)+2NaOH(aq) → Cd(OH)2(s)+2Na+(aq)
If you had a 0.300 L solution containing 0.0220 M of Cd2+(aq) , and you wished to add enough 1.25 M NaOH(aq) to precipitate all of the metal, what is the minimum amount of the NaOH(aq) solution you would need to add? Assume that the NaOH(aq) solution is the only source of OH−(aq) for the precipitation.
Answer:
The minimum amount of NaOH(aq) solution needed to add is 0.0560 L. This can be calculated by using the following equation:
Moles of Cd2+ = 0.0220 M x 0.300 L = 0.0066 mol
Moles of NaOH = 0.0066 mol x 2 = 0.0132 mol
Volume of NaOH = 0.0132 mol/1.25 M = 0.0560 L
Explanation: