Que. 1. Gallium has 2 naturally occuring Isotopes with mass numbers 69 & 71 respectively. What is the percentage abundance of both Isotopes if their relative atomic mass is equal to 70.59 Amu (Atomic mass Unit)
Isotopes are atoms of the same element that have different masses. The relative atomic mass (am) is a weighted average that takes into account the abundance of each isotope. We can calculate the relative atomic mass using the following expression.
[tex]am = \frac{\Sigma m_i \times ab_i}{100}[/tex]
where,
mi: mass of each isotopeabi: percent abundance of each isotopeFor Gallium,
[tex]70.59 amu = \frac{69 amu\ x + 71 amu\ y}{100}[/tex] [1]
where "x" and "y" are the unknown abundances.
We also know that the sum of both abundances must be 100%.
x + y = 100
y = 100 - x [2]
If we replace [2] in [1], we get
[tex]70.59 amu = \frac{69 amu\ x + 71 amu\ (100-x)}{100} \\7059 amu = -2 amu\ x + 7100amu \\x = 20.5[/tex]
Then, in [2]
y = 100 - x = 100 - 20.5 = 79.5
In conclusion, Ga-69 has an abundance of 20.5% and Ga-71 has an abundance of 79.5%.
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Câu 36: _VD _Hình lập phương có thể tích là 1253 thì diện tích đáy là:
A. cm2 B. 5cm2 C. 25cm2 D. 52cm2
Answer:
c
Explanation:
Cạnh của hình lập phương là
³\(125 = 5cm
Diện tích đáy của hình lập phương là
5²=25cm²
Đáp án C
Unknown # 21
Flame Test Color: Lilac
Addition of HCl(aq)= NR (No Reaction)
Addition of HCl(aq) and BaCl2(aq)= White precipitate
Addition of HNO3(aq) and AgNO3(aq)= NR (No Reaction)
What is the unknown ionic compund molecular formula?
Which of the following materials contains a base?
a. Stomach digestive juices
b. Orange juice
c. Ammonia window cleaner
d. Vinegar
Answer:
c. ammonia window cleaner
Explanation:
Window cleaners contain ammonia (a base) for the purpose of removing the dust and grease on the windows.
digestive juices, orange(a citrus) juice, and vinegar are all highly acidic.
... give me brainliest please :)) ...
What is the formula for the compound iodine trichoride?
Answer:
Cl 3 I
Explanation:
Molecular Weight. 233.36. Appearance. Red-orange to brown powder or chunks. Melting Point. 63 °C
Which of the following pairs of elements will form ionic bonds with each
other?
A. Silver (Ag) and silver (Ag)
B. Lithium (Li) and iodine (1)
C. Bromine (Br) and bromine (Br)
D. Carbon (C) and chlorine (CI)
Answer:
B. Lithium (Li) and iodine (1)
Explanation:
Ionic bond is a type of chemical bond that is formed between a metallic element and a non metallic element. The positive charge of the metallic ion is attracted to the negative charge of the non metallic ion to form an ionic bond.
According to the options given in this question, lithium and iodine will form an IONIC bond because lithium is a cation (+ve ion) while iodine is an anion (-ve).
e) Hydrogen gas is a non-metal and can be prepared in a laboratory Explain why hydrogen gas is collected over water.
Answer:
to collect pure hydrogen and avoid mixing with air
to make 400 gram solution with a mass by a mass concentration of 6 % how much salt and water you need to mix
Answer:
[tex]400 \div 6 \\ \\ [/tex]
what is the anode material used in the extraction of aluminium by electrolysis and why it needs to be changed at interval
Answer:
the anode material is graphite(replaceable graphite rods).
The oxygen gas burns away the anode as Carbon dioxide therefore the anode must be replaced continuously.
Exploring the Electromagnetic Spectrum
Assemble the electromagnetic spectrum by dragging each piece to the correct place on the wavelength scale.
Visible
10-2
10-7
10
10-9
10
-5
Wavelength (cm)
(PLEASE HELP!!)
Answer:
See explanation
Explanation:
When dealing with the Electromagnetic Spectrum, one should remember the acronym ROYGBIV. This will apply to visible spectrum but the non-visible spectra can de logically deduced from the sequence. That is ...
R-Red > O-Orange > Y-Yellow > G-Green > B-Blue > I-Indigo > V-Violet
In relation to the three wave properties; wavelength (λ), frequency (ν) & energy (ΔE) ...
Wavelengths => Long λ Short λ
Frequency => Low ν High ν
Energy => Low ΔE High ΔE
Note that all 'L's' are on the 'Left'
On Left => Long wavelengths, Low frequency & Low energy; the 'opposites' are on 'the other end of the list'.
Therefore for other wavelengths outside the visible spectrum set up as follows, start with visible spectrum in the middle and insert the invisible spectra of interest.
Long λ <= Visible (R.0.Y.G.B.I.V.) => Short λ
λ (cm): 10¹ 10⁻² 10⁻³ (10⁻⁵- 10⁻⁶) 10⁻⁷ 10⁻⁹ (10⁻¹¹ - 10⁻¹³)
[radio > microwave > IR > visible > UV > X-Rays > Gamma]
Hope this helps :-)
What is the chemical formula of Sulphuric Acid:-
Answer:
sulphuric acid's formula is H²SO⁴
Explanation:
HOPE U WILL FOLLOW
What is the AHsol for LiF → Lit + F-? The lattice energy is -1,036 kJ/
mol, the enthalpy of hydration for Lit is -499
kJ/mol, and the enthalpy of hydration for F-is-431 kJ/mol. Use A Hooi = -A Hat + AHhydr.
0-968 kJ/mol
-106 kJ/mol
106 kJ/mol
1,966 kJ/
mol
The heat of hydration is defined as the heat absorbed or evolved when one mole of a substance undergoes hydration. The heat of solution is the enthalpy change associated with he dissolution of a solute. The lattice energy is the heat. Lattice energy is the energy released when the components of the lattice are brought together from infinity.
Hence the heat of solution for LiF → Li^+ + F- is -1966 kJ/mol
Given that;
Heat of hydration = ΔH solution – ΔH lattice energy
Where,
ΔH solution = Heat of the solution
ΔH lattice energy = Lattice energy of the solution
The heat of solution or enthalpy of dissolution is defined as the enthalpy change associated with the dissolution of a solute in a solvent
From the formula above;
ΔH solution = Heat of hydration + ΔH lattice energy
Heat of hydration = [(-431) + (-499)] = -930 kJ/mol
ΔH solution = (-930) + (-1,036) = -1966 kJ/mol
Hence the heat of solution for LiF → Li^+ + F- is -1966 kJ/mol
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Which of the following would tell you that a weak base is present?
A. An indicator added to the solution turns green-blue.
B. If there is a high reaction rate.
C. If the pH of the solution is close to 14.
D. If the solution is a good conductor of electricity.
Answer:
A. An indicator added to the solution turns green-blue.
Explanation:
A pH scale measures the concentration of hydrogen ions in acidic and alkaline solutions.
In chemistry, pH literally means the power of hydrogen ions and it is a measure of the molar concentration of hydrogen ions in a particular solution; thus, specifying the acidity, neutrality or basicity of any chemical solution.
Mathematically, the pH of a solution is given by the formula;
[tex] pH = -log_{10}(H^{+}) [/tex]
On a pH scale, a solution with a pH of 7 is neutral, a solution with a pH below 7 is acidic and it's basic (alkaline) when it's pH is above 7.
A pH indicator can be defined as a compound (substance) that indicates the concentration of hydrogen ions present in a solution by changing its color over a narrow range of pH values.
A pH range of 1 to 3 (1 - 3) represents a strong acid with a red color.
When an indicator added to a solution turns green-blue, it simply means that a weak base is present.
15. How many moles of CaCl are in 250. mL of 3.00 M of CaCl solution?
a. 750. mol
b. 1.33 mol
C. 83.3 mol
d. 0.750 mol
e. 3.00 mol
Which statements are true in regard to the VSEPR theory?
Select all that apply.
Molecules acquire a shape that results in the greatest charge.
Molecules acquire a shape that minimizes the repulsions of electron groups.
Molecules acquire a shape that maximizes the distance of electron groups.
Molecules acquire a shape that results in the lowest possible energy state.
The correct option is D. 2) Anti-bonding electrons or lone pairs. These lone pairs, and bonds helps to form the shape which keeps these electrons separate as possible.
Formal charge is calculated by assigning each atom _____ the bonding electrons that it shares. Oxidation number is determined by assigning all the shared electrons of a particular bond to the atom with the _____ electronegativity. Multiple choice question. half; higher half; lower all; lower all; higher
Answer:
A). half, higher
Explanation:
The Formal charge is elaborated as the 'allocated charge to a molecules' atom' on the basis of the assumption that the electrons present in the chemical bond are equally split among the atoms. It is estimated by 'halving the no. of bonding electrons that encircle the atom.
While Oxidation number is characterized as the 'hypothetical charge of an atom that is present within a molecule.' It is also defined as 'the actual number of lost or gained electrons or the rate at which the electrons are gained or lost by an atom to develop a chemical bond along with the other atom.' It is calculated by allocating or sharing the electrons having the higher electronegativity belonging to a specific bond with the other. Thus, option A is the correct answer.
How did elements get to earth?
the universe formed through the big bang explosion, all of the elements on Earth have been cooked for billions of years in stars and then released in the universe through super- nova explosions.
Organisms do not adapt as a result of competition for resources.
Answer:
The given statement is False.
The organisms adapt as a result of competition for resources. Different places have different organisms suited for that particular places.
The animals living at a particular place compete for the resources available and the nature selects the organism that has won the competition for resources.
The organisms are evolved as a result of competition for resources
Answer:
I just wanted to say the other person is totally right.
this statement is false.
What is the name for the compound li2so4
Answer:
Explanation:
Lithium Sulphate
Answer:
Lithium sulfate is a white inorganic salt with the formula Li2SO4. It is the lithium salt of sulfuric acid.
Calculate K for 2CO2(g) ⇔ 2CO(g) + O2(g)
given that the equilibrium concentrations of carbon monoxide, oxygen and carbon dioxide are 2.0 x 10-6 M, 1.0 x 10-6 M, and 0.25 M respectively.
Explanation:
here's the answer to your question
What do Van der Waals forces do?
Answer:
they are weak forces that attract neutral molecules to one another
Explanation:
particles in liquid or air vibrate and move constantly thus they collide
As a person BAC level increase it becomes difficult for them to judge their vehicle distances and speed
Answer:
TRUE
Explanation:
The blood alcohol content is also known as the blood alcohol level or the blood alcohol concentration. It is defined as the measurement of the alcohol intoxication in the body and is used for the legal or the medical purposes.
When the BAC increases in the person's body, the person started to loose clear vision, loss of short term memory, poor muscle coordination, impaired perception and face difficulty in concentrating. Thus it becomes very difficult for a person to drive a car or ride a bike whose BAC has increased.
The driver cannot properly judge the distances between the vehicle and the speed of the vehicle.
Hence the answer is TRUE.
Is the following change an oxidation or reduction?
manganese (IV) oxide to manganese (III) oxide.
Answer:
12113
Explanation:
step by step:no
What are isotopes_???
Answer:
Below!
Explanation:
Isotopes are elements with a similar chemical makeup and the same atomic number, but a different atomic mass and number of neutrons . An example of this would be carbon-12, carbon-13, and carbon-14. Three isotopes of the element carbon that have the same 6 protons but have a different neutron count. A simple way to explain isotopes would be to say that they are just different "versions" of an element.
Hope this helps ya! Best of luck <3
Determinar el volumen de 20 kg de benceno si su densidad es de 0,88g/cm3
Answer:
volume = mass/ densidad
0.88g/cm3 = 880kg/m3
v=20kg/880kg/m3
v=0.02272727272
o puede ser 0.0227
o tambien puede ser 0.023
: Axit sunfurơ (H2SO3) là axit yếu, ngay trong dung dịch H2SO3 cũng bị phân hủy thành chất X và H2O. X là:
A. H2S B. SO2 C. H2SO4 D. SO3
Answer:
DD
Explanation:
Question 22 of 30
What is the balanced form of the chemical equation shown below?
C6H1206(s) + O2(g) → H2O(l) + CO2(9)
A. CH 0(s) + O2(g) → H2O(1) + CO2(g)
B. CoH1206(s) + O2(g) → 12H2O(l) + 6CO2(g)
C. C6H1206(s) + O2(g) → H20(1) + CO2(g)
D. CoH 206(s) + 602(g) → 6H2O(l) + 6CO2(g)
SU
Answer:
C6H12O6+6O2--->6CO2+6H2O
Explanation:
So I went through all the answers and could not find the right one amongst. If I'm not wrong the reaction above is the reaction for respiration. The nearest answer is D but unfortunately the first reactant isn't in accordance with that which the question has given.
When 4.2 gram of sodium bicarbonate reacts with 10.0 g of acetic acid, the product contains 2.2 g of carbon dioxide and residue cxontaining water and Sodium acetate. The mass of the residue will be:- *
Na2CO3+2HCl⟶2NaCl+H2O+CO2
Law of conservation of mass- It states that for any closed system, the mass of the system always remain constant over time, as mass of system cannot change. Therefore, (mass of Na2CO3+ mass of HCl) should be equal to (mass of residue + mass of CO2)
Mass of Na2CO3=4.2 g
Mass of HCl=10 g
Mass of residue =12 g
Mass of CO2=2.2 g
∴ Mass of Na2CO3+ Mass of HCl=14.2 g
and Mass of residue + Mass of CO2=14.2 g
Therefore, they follow law of conservation of mass.
Teniendo en cuenta la imagen anterior responde las siguientes preguntas:
1. ¿Cuál es la tendencia general de la electronegatividad a lo largo de un periodo? a. Aumentar
b. Disminuir
c. La electronegatividad es igual en todos
d. no hay ninguna tendencia
2. Ordene los átomos siguientes de menor a mayor electronegatividad: Li, Ca, C y Se a. Li
b. Se
c. Ca
d. Se
3. ¿Cuál de los átomos siguientes es el que posee mayor potencial de ionización? a. P
b. Sb
c. As
d. N
4. De las siguientes definiciones, ¿Cuál se acerca más a lo que es la electronegatividad? a. Es la tendencia relativa que presenta un elemento a atraer hacia si electrones b. Es la tendencia relativa de un átomo en estado gaseoso a repeler los electrones c. es la carga negativa que representa una unión
d. es la diferencia entre el potencial de ionización y la afinidad electrónica de un elemento. rapido es para hoy
1. La tendencia general de la electronegatividad durante un período es que la electronegatividad aumenta durante un período
La opción correcta es a. Incremento
Razón
El número de electrones de valencia aumenta durante un período, por lo
que aumentar la tendencia del átomo a lograr la estructura de octeto
estable requiriendo atraer (cada vez menos a medida que avanzamos por
el período desde la izquierda a la derecha) compartieron electrones
cuando se forman enlaces, lo que aumenta electronegatividad
2. El orden de electronegatividad creciente es Li → Ca → C → Se
Razón
La electronegatividad aumenta a lo largo del período y disminuye en el grupo.
Las ubicaciones de los elementos dados son;
Litio, Li; Grupo 1 período 2 Calcio, Ca; Grupo 2 período 4 Carbono, C; Grupo 14 período 2 Selenio Se; Grupo 16 período 4Primero escribimos los elementos con los números de grupo más altos,
que son Se y C, después de lo cual tenemos Ca, luego Li, por lo tanto, en
orden creciente, obtenemos;
Li → Ca → C → Se
3. La opción correcta es d. N (nitrógeno)
Razón
El potencial de ionización representa la energía necesaria para eliminar un electrón de un átomo.
El potencial de ionización disminuye en un grupo y aumenta a lo largo de un período de izquierda a derecha.
Tenemos;
Fósforo, P; Grupo 15 período 3 Antimonio, Sb; Grupo 15 período 5 Arsénico, As; Grupo 15 período 4 Nitrógeno, N; Grupo 15 período 2Por lo tanto, el elemento con mayor potencial de ionización es aquel que se encuentra en la posición más alta en el grupo 15 entre los elementos dados, que es el nitrógeno, N
4. La opción correcta para la definición de electronegatividad es la opción (a);
un. Es la tendencia relativa de un elemento a atraer electrones hacia sí mismo.
Razón
La electronegatividad es la capacidad relativa de un elemento dado para atraer electrones compartidos hacia sí mismo.
Por lo tanto, la opción correcta es a. es la tendencia relativa de un elemento a atraer electrones hacia sí mismo
Obtenga más información sobre la electronegatividad y la energía de ionización aquí;
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What is the energy of a photon that emits a light of
frequency 6.42 x 1014 Hz?
A. 4.67 x 10-19 J
B. 4.25 x 10-19
C. 3.10 x 10-19 J
D. 9.69 x 10-19 J
Answer:
Option B is correct [4.25 x 10-19J]
Explanation:
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4.78×[tex]10^{-19}[/tex] J is the energy of a photon that emits light of
frequency 6.42 x[tex]10^{14}[/tex] Hz.
What is the frequency?Frequency is the rate at which current changes direction per second. The energy of a single photon is given by:
E =hν
where
E is the energy
h is the Planck constant
f is the frequency of the light
The chemical equation for the energy of a photon is given by:
E =hν , where h is the Planck constant and ν is the frequency.
E =hν = 6.626×[tex]10^{-34}[/tex] Js × 7.21×[tex]10^ {14}[/tex]
[tex]s^{-1}[/tex] = 4.78 ×[tex]10^{-19}[/tex] J
Hence, 4.78×[tex]10^{-19}[/tex] J is the energy of a photon that emits light of
frequency 6.42 x[tex]10^{14}[/tex] Hz.
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