ASAP:
The estimated atomic mass of silicon could be Choose... amu because the Choose.. abundant isotope is Choose...
Answers
Answer:
The estimated atomic of silicon is 28.082 a.m.u.
Explanation:
The estimated atomic mass of silicon ([tex]M_{Si, est}[/tex]), in a.m.u., is equal to the weighted average of atomic masses of silicon available in nature and in terms of their abundances:
[tex]M_{Si, est} = r_{1}\cdot M_{Si-28} + r_{2} \cdot M_{Si-29} + r_{3}\cdot M_{Si-30}[/tex] (1)
Where:
[tex]r_{1}[/tex], [tex]r_{2}[/tex], [tex]r_{3}[/tex] - Relative abundance of each isotope, no unit.
[tex]M_{Si-28}[/tex], [tex]M_{Si-29}[/tex], [tex]M_{Si-30}[/tex] - Atomic mass of each isotope, in a.m.u.
If we know that [tex]M_{Si-28} = 27.976\,a.m.u.[/tex], [tex]M_{Si-29} = 28.976\,a.m.u.[/tex], [tex]M_{Si-30} = 29.974\,a.m.u.[/tex], [tex]r_{1} = \frac{92.22}{100}[/tex], [tex]r_{2} = \frac{4.68}{100}[/tex] and [tex]r_{3} = \frac{3.09}{100}[/tex], then the estimated atomic mass of silicon is:
[tex]M_{Si, est} = r_{1}\cdot M_{Si-28} + r_{2} \cdot M_{Si-29} + r_{3}\cdot M_{Si-30}[/tex]
[tex]M_{Si,est} = \left(\frac{92.22}{100} \right)\cdot (27.976\,a.m.u.) + \left(\frac{4.68}{100} \right)\cdot (28.976\,a.m.u.) + \left(\frac{3.09}{100} \right)\cdot (29.974\,a.m.u.)[/tex]
[tex]M_{Si, est} = 28.082\,a.m.u.[/tex]
The estimated atomic of silicon is 28.082 a.m.u.
Related Questions
I NEED HELP WITH CHEM PLEASE HAVE A DECENT ANSWER
Answers
Answer:
x is HCl because pH = 2 (acid and it reacted with Mg plus it turned litmus paper to red)
y is NaOH because pH = 10 (base and turned litmus paper to blue)
z is NaCl because pH = 7 (neutral and no reaction to litmus paper and Mg)
Find the molecular weight of CO
Answers
Answer:
The molecular weight of CO is 28.01g/mole.
A Cartesian Diver demonstrates which of the following?
A. the inverse relationship of Boyle's law
B. the direct relationship of Boyle's law
C. squeezing the bottle, pushes the test tube down.
D. the density of a gas is less than the density of water.
Answers
Answer:
(a) The inverse relationship of Boyle's law.
Explanation:
A Cartesian diver is used in scientific experiments to demonstrate the certain principles in science such as;
i. The principle of floatation or the Archimedes' principle.
ii. The implication of the ideal gas law as seen in, for example, Boyle's law and pressure law,
iii. Pascal's principle.
The diver demonstrates that given a large soft drink bottle containing water and a medicine dropper at its top, squeezing the bottle pushes the dropper down to the bottom. When the squeezing stops, the dropper comes back to the top again.
Now using this to demonstrate Boyle's law (which shows the relationship between pressure and volume where increase in one results in the decrease in the other), when the bottle is squeezed (which means pressure is increased on the bottle), the water is forced into the medicine dropper thereby decreasing the volume of air in the dropper. Removing pressure on the bottle produces an opposite effect.
If your end product is 1.5 moles of KMnO4, how many moles of manganese oxide were used in the reaction?
The equation for the production of potassium permanganate is as follows:
2 MnO2 + 4 KOH + O2 → 2 KMnO4 + 2 KOH + H2
You must show all work
Answers
Answer:
1.5 moles of KMnO4 will be produced from 1.5 moles of MnO2
Explanation:
The balanced equation of this chemical reaction is
2 MnO2 + 4 KOH + O2 → 2 KMnO4 + 2 KOH + H2
2 moles of MnO2 produces 2 moles of KMnO4
That means 1 moles of KMnO4 will be produced from 1 moles of MnO2
Hence, 1.5 moles of KMnO4 will be produced from 1.5 moles of MnO2
The moles of manganese oxide were used in the reaction is 1.5 moles.
What is stoichiometry?Stoichiometry of any reaction tells about the relative amount of species present before and after the chemical reaction.
Given chemical reaction is:
2MnO₂ + 4KOH + O₂ → 2KMnO₄ + 2KOH + H₂
From the stoichiometry of the reaction, it is clear that same moles of manganese oxide and potassium permanganate is involved in the reaction.
2 moles of KMnO₄ = produce by 2 moles of MnO₂
1.5 moles of KMnO₄ = produce by 2/2×1.5=1.5 moles of MnO₂
Hence, required moles are 1.5 moles.
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What is diffusion? How does the motion of gas molecules explain how a gas diffuses throughout a room?
Answers
Answer:
Diffusion in gases
Diffusion is driven by differences in concentration. When chemical substances such as perfume are let loose in a room, their particles mix with the particles of air. The particles of smelly gas are free to move quickly in all directions
Explanation:
hope this helps
Someone please help me
Answers
Answer:reflection
Explanation:
Molar mass of propan-1-ol
Answers
Answer:
60g/mol.
Explanation:
TO FIND :-
Molar mass of Propan-1-olFACTS TO KNOW BEFORE FINDING ANSWER :-
Chemical formula of Propan-1-ol = CH₃CH₂CH₂OH [or] C₃H₈OMolar mass of C = 12g/mol.Molar mass of H = 1g/mol.Molar mass of O = 16g/mol.SOLUTION :-
Molar mass of C₃H₈O = 3(Molar mass of C) + 8(Molar mass of H) + 1(Molar mass of O)
⇒ Molar mass of C₃H₈O = (3×12) + (8×1) + 16 = 36 + 8 + 16 = 60g/mol.
which atom has the highest ionization energy? magnesium, barium, calcium, beryllium
Answers
Explanation:
Beryllium has the highest Ionization energy
An isotope undergoes radioactive decay. The new isotope that forms has an atomic number that is 2 less than the original isotope’s.
Which kind of decay has occurred, and how do you know?
1)alpha decay because alpha particles have a large mass
2)beta decay because beta particles can have negative charge
3)alpha decay because alpha particles have two protons and two neutrons
4)gamma decay because gamma rays are photons
Answers
Answer:
3)alpha decay because alpha particles have two protons and two neutrons
Explanation:
When a radioactive isotope undergoes a decay, a daughter nucleus or nuclei is/are formed. The mass number and atomic number of the daughter nucleus gives us an idea of the nature of radioactive decay that the parent nucleus underwent.
If the daughter mass number of the daughter nucleus is four units less than that of the parent nucleus and the atomic number of the daughter nucleus is two units less than that of the parent, then such a decay is an alpha decay.
An alpha particle has two protons and two neutrons thus it has a mass number of 4 and an atomic number of two.
chemical formula for diethyl ester dimethyl ammonium chloride
-PLEASE HELP ASAP
Answers
An engine operates on a Carnot cycle that uses 1mole of an ideal gas as the
working substance and operates from a most compressed stage of 100 Nm and
327 K. It expands isothermally to a pressure of 90 Nm and then adiabatically to a
most expanded stage of 27 K. Calculate the AU, 9, and w for each step. Calculate
the net work done and the efficiency of the cycle [Cv,m for the gas) is 25 J/k/mol.
Answers
Answer:
Step 1;
q = w = -0.52571 kJ, ΔS = 0.876 J/K
Step 2
q = 0, w = ΔU = -7.5 kJ, ΔH = -5.00574 kJ
Explanation:
The given parameters are;
[tex]P_i[/tex] = 100 N·m
[tex]T_i[/tex] = 327 K
[tex]P_f[/tex] = 90 N·m
Step 1
For isothermal expansion, we have;
ΔU = ΔH = 0
w = n·R·T·ln([tex]P_f[/tex]/[tex]P_i[/tex]) = 1 × 8.314 × 600.15 × ln(90/100) = -525.71
w ≈ -0.52571 kJ
At state 1, q = w = -0.52571 kJ
ΔS = -n·R·ln([tex]P_f[/tex]/[tex]P_i[/tex]) = -1 × 8.314 × ln(90/100) ≈ 0.876
ΔS ≈ 0.876 J/K
Step 2
q = 0 for adiabatic process
ΔU = 25×(27 - 327) = -7,500
w = ΔU = -7.5 kJ
ΔH = ΔU + n·R·ΔT
ΔH = -7,500 + 8.3142 × 300 = -5,005.74
ΔH = ΔU = -5.00574 kJ
The diagram represents a beaker containing sugar,water, and sand. The sugar is dissolved in the water, creating a solution. The sand has settled to the bottom of the beaker. Describe one method to separate the sand from the other substances in the beaker.
Answers
Answer:
boiling
Explanation:
because heat dissolve sugar and not dissolve sand
One method to separate the sand from the other substances in the beaker is filtration.
What is separation?A separation process is a method for separating two or more separate product mixtures from a mixture or solution of chemical ingredients.
To put it another way, it's a scientific method for discriminating between two or more substances in order to achieve purity. On of the simple method of separating sand from the solution of water and sugar is filtration. As sand is insoluble in water so by the use of filter we can separate out sand.Hence one separation method is filtration.
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Energy that is made from the power of moving water
a
b
ОООО
wind
hydroelectric
coal
с
d
biomass
Answers
Hydroelectric energy is produced.
Use an example of how we use an informal kind of scientific method in our everyday lives
Answers
Answer:
baking cookies
Explanation:
One example of using a scientific method is baking cookies. You make a hypothesis that you cookies will be done in 15 minutes. Then, after 15 minutes, you see that either your hypothesis was correct and you cookies are perfect or you need to bake them longer making you hypothesis incorrect. (please change the wording up a bit if you want. i tried to make it make the most sense)
Answer:
Explanation:
When you loose your phone. You try to remember where you last used your phone, and question yourself where you might have left it. If you say that you probably left it in the kitchen, that would be like your hypothesis. Then you go look for it where you thought you left it which would be your experiment. If maybe it is not there that would be like your conclusion so you would reject your hypothesis because it was wrong. Then you try the scientific method again but with a different hypothesis, like that maybe you left it in the living room. You do your experiment which is when you go look for it. In the conclusion if your hypothesis was right you accept your hypothesis. That can be an example of how we use the scientific method in our everyday lives.
Predict the total pressure in Container C if the initial pressure in
Container A was tripled and Container B was reduced by one-third then
mixed together in Container C.
SHOW ALL WORK
Answers
Answer:
[tex]98 \times x6x \geqslant {36461 { {3 \frac{ \sqrt[ |?| ]{?} }{?} }^{2} }^{?} }^{2} [/tex]
okay
6 a 100 sample of Au - 198 Au 198 be? Decays to 3.125 g in 13.5 days, what would the half-life of au198 be?
Answers
Answer:
Half-life = 2.7 days
Explanation:
The radioactive decay of an isotope follows the equation:
Ln[A] = -kt + ln[A]₀
Where [A] could be taken as the amount of A after t time, k is decay constant, [A]₀ initial amount of A.
Replacing to solve k:
Ln[3.125g] = -k*13.5days + ln[100g]
-3.465736 = -k*13.5days
k = 0.2567days⁻¹
Half-life is:
half-life = ln2 / k
Half-life = 2.7 days
If hydrochloric acid is obtained commercially at a concentration of 12.1M, how many milliliters of 12.1M HCl(aq) must be used to prepare 2.00x103mL of 0.500M HCL(aq)?
Answers
Answer:
[tex]V_1=82.6mL[/tex]
Explanation:
Hello there!
In this case, according to this question, we will need to deal with this dilution problem, because it is asking for the volume of a 12.1-M stock solution of HCl. In such a way, we can use the following equation, under the assumption of no change in the number of moles in the solution:
[tex]M_2V_2=M_1V_1[/tex]
Thus, we solve for the initial volume, V1, as shown below:
[tex]V_1=\frac{M_2V_2}{M_1}[/tex]
And plug in the initial concentration and final concentration and volume to obtain:
[tex]V_1=\frac{2000mL*0.500M}{12.1M}\\\\V_1=82.6mL[/tex]
Regards!
What type of reaction is Al + KOH +H2O = K[Al(OH)4] + H2
Answers
Answer:
Al + 2 KOH + 6 H 2O → 3 H 2 + 2 K[Al(OH) 4] This is a complexation reaction: K[Al(OH) 4] is the formed complex. ; Silvery-white, malleable, ductile, odorless metal.
Explanation:
I hope this help
The element in group 14, period 3 of the periodic table is classified as a?
1. Metal
2. Noble gas
3. Metalloid
4. nonmetal
Answers
Answer:
It's a Metalloid
Explanation:
CaCl2
Ca +
CI2
Balance this equation
Answers
To balance Ca + Cl2 = CaCl2 you'll need to be sure to count all of atoms on each side of the chemical equation.
Once you know how many of each type of atom you can only change the coefficients (the numbers in front of atoms or compounds) to balance the equation for Calcium + Chlorine gas.
The combustion of acetylene gas is represented by this equation: 2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(g)
How many moles of H2O are produced when 64.0 g C2H2 burn in oxygen?
M.M
H2O = 18.02 g/mol
C2H2 = 26.04 g/mol
2.46 moles H2O
5.13 moles H2O
4.92 moles H2O
2.00 moles H2O
Answers
Answer:
Approximately [tex]2.46\; \rm mol[/tex].
Explanation:
Make use of the molar mass data ([tex]M({\rm C_2H_2}) = 26.04\; \rm g \cdot mol^{-1}[/tex]) to calculate the number of moles of molecules in that [tex]64.0\; \rm g[/tex] of [tex]\rm C_2H_2[/tex]:
[tex]\begin{aligned}n({\rm C_2H_2}) &= \frac{m({\rm C_2H_2})}{M} \\ &= \frac{64.0\; \rm g}{26.04\; \rm g\cdot mol^{-1}}\approx 2.46\; \rm mol\end{aligned}[/tex].
Make sure that the equation for this reaction is balanced.
Coefficient of [tex]\rm C_2H_2[/tex] in this equation: [tex]2[/tex].
Coefficient of [tex]\rm H_2O[/tex] in this equation: [tex]2[/tex].
In other words, for every two moles of [tex]\rm C_2H_2[/tex] that this reaction consumes, two moles of [tex]\rm H_2O[/tex] would be produced.
Equivalently, for every mole of [tex]\rm C_2H_2[/tex] that this reaction consumes, one mole of [tex]\rm H_2O[/tex] would be produced.
Hence the ratio: [tex]\displaystyle \frac{n({\rm H_2O})}{n({\rm C_2H_2})} = \frac{2}{2} = 1[/tex].
Apply this ratio to find the number of moles of [tex]\rm H_2O[/tex] that this reaction would have produced:
[tex]\begin{aligned}n({\rm H_2O}) &= n({\rm C_2H_2}) \cdot \frac{n({\rm H_2O})}{n({\rm C_2H_2})} \\ &\approx 2.46\; \rm mol \times 1 = 2.46\; \rm mol\end{aligned}[/tex].
10 ejemplos de disoluciones identificando el soluto y el solvente y el tipo de disolucion que corresponde
Answers
Answer:
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You perform an experiment to determine the density of the penny in the lab. To do this you count out 10 pennies and measure their mass on an analytical balance. The mass of the 10 pennies was found to be 24.0416 grams. To determine the volume of the pennies you add water to a graduated cylinder and the volume is found to be 20.23 mL. After 10 pennies have been carefully added to the graduated cylinder, the volume is now found to be 23.13 mL. Calculate the density of the penny in g/mL and report your answer to the correct number of significant figures.
Answers
Answer:
8.29g/mL
Explanation:
Density (g/mL) = mass(g)/volume(mL)
According to this question, an experiment is conducted on the density of penny in the laboratory found out that the masses of the 10 pennies was found to be 24.0416g while the volume of the pennies is as follows:
Volume of water + graduated cylinder= 20.23 mL.
Volume of pennies + water = 23.13 mL.
Hence, volume of pennies is 23.13 - 20.23
= 2.9mL
Density = 24.042g ÷ 2.9mL
Density = 8.29g/mL
Which of the following best describes density?
- the relationship between length and mass
- the relationship between volume and area
- the relationship between mass and area
- the relationship between mass and volume
Answers
Answer:
the relationship between mass and volume
How many elements in a periodic table?
Answers
Which of the following must be
TRUE if a solution is to be
considered acidic?
A. [H^+] < [OH)
B. [H^+] > [OH ]
C. KW= [H^+] /[OH]
D. [H^+] =[OH)
Answers
Answer:
c
Explanation:
kw=h+bls
Which of the following elements would not be a good conductor of electricity?
sodium
iron
calcium
sulfur
Answers
Answer:
azufre
Explanation:
El azufre es un mal conductor del calor y aislante de la electricidad.
Covalent bonded atoms make up what
Answers
A student investigates the reaction between sodium hydroxide solution and dilute sulfuric acid.
He does a titration to find the concentration of the sulfuric acid.
(a) Give the colour change of the methyl orange indicator at the end-point.
Answers
Explanation:
the colour change will be from orange to pink
The color change of the methyl orange indicator at the end-point will show orange to pink.
What is indicator?In an acidic or basic medium, an indicator is just a material that changes color. Indicators are termed indicators because they show one color in an acidic media and different colors in a basic medium. Indicators come in a variety of shapes and sizes: Natural indicators are indicators acquired from natural sources.
It is a just a acid base reaction in which methyl orange acts as a indicator.
In this reaction, when sodium hydroxide solution and dilute sulfuric acid are reacts with each other then after using( indicator)methyl orange the color will be change form orange to pink which indicates the nature of solution will be acidic.
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How do I calculate the pOH of a Solution at 25℃ with a [OH-1] = 6.5 x 10-9 M and state whether the Solution is Acidic, Basic, or Neutral?
Answers
Answer:
pOH = 8.19
Acidic solution (pH < 7.0)
Explanation:
The pOH of the solution is defined as:
pOH = - log [OH⁻]
Since we have [OH⁻] = 6.5 x 10⁻⁹ M, we calculate the pOH as follows:
pOH = - log (6.5 x 10⁻⁹) = 8.19
To know if the solution is acidic, neutral or basic, we have to calculate the pH from the value of pOH:
pH + pOH = 14
⇒ pH = 14 - pOH = 14 - 8.19 = 5.81
The solution is acidic because pH < 7.0.