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
The chemical equation for zinc in hydrochloric acid is: Zn + HCI = ZnCl2 + H2
Does the above equation demonstrate the law of conservation of mass as it is currently written? Explain why or why not.
Answers
Answer: No it does not
Explanation:
The law of conservation of mass states that mass is neither created nor destroyed and in this equation you start with 1 molecule of Cl and 1 of H, but on the reactants side you end up with 2 of each. To make it follow the law of conservation of mass you would have to balance the equation
how many moles are in 0.14g of Nitrogen, N2?
Answers
Answer:
0.01 moles
Explanation:
14 g contains 1 mole
0.14g contains> (0.14*1)/14
= 0.01 moles
The back of a water droplet acts as a mirror. When light hits the back of the water droplet, it bounces back to our eyes. This is called ____________.
Answers
112 g of aluminum carbide react with 174 g water to produce methane and aluminum hydroxide in the reaction shown below.
2 Al4C3(s) + 12 H2O(l) → 3 CH4(g) + 4 Al(OH)3(s)
If aluminum carbide is the limiting reactant, how many moles of the excess reactant are left over
a
37.3 mol
b
4.68 mol
c
7.33 mol
d
131.94 mol
Answers
Answer: 4.999 moles of excess reactant will be left over.
Explanation:
Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.
Excess reagent is defined as the reagent which is left behind after the completion of the reaction.
The number of moles is defined as the ratio of the mass of a substance to its molar mass.
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] .....(1)
Given mass of aluminium carbide = 112 g
Molar mass of aluminium carbide = 143.96 g/mol
Putting values in equation 1:
[tex]\text{Moles of aluminium carbide}=\frac{112g}{143.96g/mol}=0.778mol[/tex]
For the given chemical reaction:
[tex]2Al_4C_3(s)+12H_2O(l)\rightarrow 3CH_4(g)+4Al(OH)_3(s)[/tex]
By the stoichiometry of the reaction:
2 moles of aluminium carbide reacts with 12 moles of water
So, 0.778 moles of aluminium carbide will react with = [tex]\frac{12}{2}\times 0.778=4.668 mol[/tex] of water
Given mass of water = 174 g
Molar mass of water = 18 g/mol
Putting values in equation 1:
[tex]\text{Moles of water}=\frac{174g}{18g/mol}=9.667mol[/tex]
Moles of excess reactant (water) left = 9.667 - 4.668 = 4.999 moles
Hence, 4.999 moles of excess reactant will be left over.
Any change in average weather conditions on Earth that lasts for at least several decades is called
Answers
Answer:climate change
Explanation:
Gas particles that are at low temperature and high pressure and are close to changing phases are considered:
a)Real Gases
b)Ideal Gases
c)Both Ideal and Real Gases
Answers
Examine the food chain below: In this specific food chain, the _______ eats plants for food. A. caterpillar B. sunshine C. bobcat D. leaf
Answers
Can someone please help, 20 points
Draw 3-ethyl-2,4-dimethyl octanoic acid
Answers
3-ethyl-2.4-dimethyl-octanoic acid
PLEASE HELP!
The specific heat of octane, C8H18(l), is 2.22 J/(g⋅K).
How much heat is needed to raise the temperature of 76.0 g of octane from 10.6 ∘C to 26.0 ∘C?
Express your answer in joules to three significant figures.
Answers
Answer:
Q = 2.60 • [tex]10^{3}[/tex] J
Explanation:
Our specific heat capacity equation is:
Q = mC∆T
Q is the energy in joules.
m is the mass of the substance.
∆T is the temperature chance.
Let's plug in what we know.
We have 76.0 g of octaneThe specific heat capacity of octane is 2.22 J/(g•K)The temperature increases from 10.6º to 26.0º (a 15.4º increase)Q = 76.0(2.22)(15.4)
Multiply.
Q = 2598.288
We want three significant figures.
Q = 2.60 • [tex]10^{3}[/tex]
or
Q = 2590 J
Hope this helps!
Answer:6,985.008
Explanation:
so the hear formula is mass times specific heat times change in temperature (kelvin) so what i did was got the change in temperature (41.4 K) and multiplied that times 2.22 J/(g•K)and multiplied that by 76 grams of Octane to get the Answer (not in scientific notation)
El petróleo crudo, es decir, en estado natural,
se encuentra embebido en las rocas porosas de
la corteza terrestre, semejante al agua en una
esponja, y no a manera de lagos subterráneos,
como se cree. Por lo general, el pozo petrolero
contiene en su parte superior una gran masa de
gas. Responde:
a) ¿Qué precauciones se deben tener en la explo-
tación del petróleo?
b) ¿Cuál es el impacto ambiental de la explotación
del petróleo?
c) ¿Qué compromisos debe cumplir una em-
presa que explota el petróleo en relación con el
medio ambiente?
Answers
If 250. ML of water are poured into the measuring cup, the volume reading is 8.45 oz . This indicates that 250. ML and 8.45 oz are equivalent. How many milliliters are in a fluid ounce based on this data?
Answers
Answer:
[tex]1oz=29.589ml[/tex]
Explanation:
From the question we are told that:
Initial Volume [tex]v_1=250ml[/tex]
Final Volume [tex]v_2=8.45oz[/tex]
Generally the equation for one ounce is mathematically given by
[tex]1oz=\frac{v_1}{v_2}[/tex]
Therefore
[tex]1oz=\frac{250}{8.45}[/tex]
[tex]1oz=29.589ml[/tex]
the tissue which continually forms new cells in plants
Answers
Answer:
Meristematic Tissues. Tissues where cells are constantly dividing are called meristems or meristematic tissues. These regions produce new cells.
Explanation:
thank me later
Please choose a claim and then answer the question below please ty I would appreciate it!
Answers
Answer:
Claim 1
Explanation:
I chose this claim because I believe that when the plates under the earth move or shift, that's what causes an earthquake and when everything starts to shake. If it was the other way around there wouldn't be any reason for an earthquake to start.
hope that helped :)
Answer:
Plates move, which can cause earthquakes.
Explanation:
Tectonic plates are always slowly moving, however sometimes they can "lock" together, creating pressure and build up. The release of this energy results in a Tectonic earthquake. Therefore, the movement of plates causes earthquakes.
When 1 mol of methane is burned at constant pressure, −890 kJ/mol of energy is released as heat. If a 1.67 g sample of methane is burned at constant pressure, what will be the value of ∆H
Answers
Answer:
[tex]\Delta H=-92.7kJ[/tex]
Explanation:
Hello there!
In this case, according to the given information, we can infer that 890 kJ of energy are released when 1 mole of methane is burned; however, to find the total heat when 1.67 grams are burned, we first need to calculate the moles in this mass of methane:
[tex]1.67gCH_4*\frac{1molCH_4}{16.04gCH_4}=0.104molCH_4[/tex]
And thus, for calculating the resulting ∆H, we proceed as follows:
[tex]\Delta H=-890kJ/mol*0.104mol\\\\\Delta H=-92.7kJ[/tex]
Regards!
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
If 10.0 grams of sodium phosphate are reacted, what mass of barium nitrate is
required?
Answers
Answer: The mass of barium nitrate required is 23.91 g
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass.
The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Given mass of sodium phosphate = 10.0 g
Molar mass of sodium phosphate = 163.94 g/mol
Plugging values in equation 1:
[tex]\text{Moles of sodium phosphate}=\frac{10.0g}{163.94g/mol}=0.061 mol[/tex]
The chemical equation for the reaction of sodium phosphate and barium nitrate follows:
[tex]3Ba(NO_3)_2+2Na_3PO_4\rightarrow Ba_3(PO_4)_2+6NaNO_3[/tex]
By the stoichiometry of the reaction:
If 2 moles of sodium phosphate reacts with 3 moles of barium nitrate
So, 0.061 moles of sodium phosphate will react with = [tex]\frac{3}{2}\times 0.061=0.0915mol[/tex] of barium nitrate
Molar mass of barium nitrate = 261.337 g/mol
Plugging values in equation 1:
[tex]\text{Mass of barium nitrate}=(0.0915mol\times 261.337g/mol)=23.91g[/tex]
Hence, the mass of barium nitrate required is 23.91 g
High levels and long periods of stress can increase a person’s risk for many diseases.
True
False
Answers
Answer:
true
Explanation:
Which of the following best describes asexual reproduction?
it produces offspring with a large amount of genetic variation
it occurs in simple organisms, such as bacteria, but not in multicellular organism such as plants and animals
it allows species to quickly adapt to environmental changes
it can be an advantage to organisms that live in a stable unchanging environment
Answers
Answer:
First Choice
it produces offspring with a large amount of genetic variation
Answer: i think this is correct.
Explanation: it occurs in simple organisms, such as bacteria, but not in multicellular organism such as plants and animals
Water can keep engines operating at low temperatures. Which property of water most likely gives it this ability?
A. it boils at around 100°C
B. it has a high heat capacity
C. it is a good lubricant
D. it can change from water to ice
Answers
Answer:
B: it has a high heat capacity
Explanation:
When any material has a high specific heat capacity/ heat capacity, it doesn't heat or cool very fast. So water can absorb more heat from the engine and can keep the engine cool or at low temperature for a longer period of time.
Which statement compares the relative strength of the electric forces that hold particles together
A. The force between two nonpolar molecules are stronger than the force between positive ions and freely moving electrons
B. The force between two polar molecules are stronger than the force between positive ions and freely moving electrons
C. The force between positive and negative ions is weaker than the force between two polar molecules
D. The force between two nonpolar molecules is weaker than the force between positive ions and freely moving electrons
Answers
A.the force between two non polar molecules are stronger than the force between positive ions and freely moving electrons
The concentration of carbon-14 in a piece of wood from an ancient burial mound indicates that two half-lives of this radioisotope have passed. If the half-life (t 1/2) for carbon-14 is 5730 years, approximately how many years ago did this sample of wood die?
Answers
If the half-life for carbon-14 is 5730 years, then it will take 11,460 years to complete die of this sample.
What is half life period?Half life period is a time of decay in which concentration of reactant is left half of its initial concentration, means half of the reactant will convert into product.
Total time of decay will be calculated as:
T = (t)ⁿ, where
t = half life time = 5730 years
n = number of half lives = 2 (given)
On putting values, we get
T = (5730)² = 11,460 years
Hence required time for decay is 11,460 years.
To know more about half life time, visit the below link:
https://brainly.com/question/2320811
Answer:
The first part is 5 and the second part is 28,650
What is the mass of a sample of NH3 containing 3.80 x 1024 molecules of NH3? (5 points)
74.8 grams
107 grams
89.4 grams
101 grams
Answers
Answer: 107 grams
Explanation: got it right on the test
The mass of a sample of f NH₃ containing 3.80 x 10²⁴ molecules of NH₃ is 107.27 grams.
What is a molecule?A molecule is a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance.
6.02214076 × 10²³ molecules constitute 1 mole of NH₃
3.80 x 10²⁴ molecules constitutes of = 6.31 moles
1 mole of NH₃ = 17 gm
11.19 mole will be = 17 X 6.31
= 107.27 grams
Therefore the mass of a sample of NH₃ containing 3.80 x 10²⁴ molecules of NH₃ is 107.27 grams.
Learn more about molecules here:
brainly.com/question/19922822
#SPJ2
is how much a material opposes electric current.
*
insulator
conductor
resistance
short circuit
Answers
Answer:
Resistance
Explanation:
Resistance is the measure of the opposition of current in a circuit.
que tipo de fermentacion es al mezclar el agua tibia con levadura
Answers
Answer:
kapsüsnwsibd bqvw j dkpövahfbjbjwv8kfb
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.
Please help me I will give brainliest to the first correct answer
Answers
Answer:
OPTIC B) HEPT-HOPE IT IS HELPFUL
when chlorine gas is passed through potassium Bromide solution Potassium Chloride and bromine are formed which is a more reactive non metal bromine or chlorine
Answers
[tex] \boxed{\boxed{\huge{ \mathbf{ \underline{ Answer} \: \: ✓ }}}}[/tex]
In a displacement reaction, more reactive element displaces less reactive element from its compound and from the above reaction we observed that, Chlorine displaces bromine from its compound (KBr) to form Potassium chloride (KCl), therefore Chlorine is more reactive non - metal.
The equation for above reaction is :
[tex] \large\boxed {\mathrm{2KBr + Cl_2 \rightarrow 2KCl + Br_2}}[/tex]
_____________________________
[tex]\mathrm{ ☠ \: TeeNForeveR \:☠ }[/tex]
which is following is used to cook food?
Answers
Answer: A process of cooking food in a pot made from unglazed and natural clay. coddling: Heating food in water kept just below the boiling point.
Explanation:
Pls answer this Il give brainiest question in picture ty
Answers
Answer:
c
Explanation:
troposphere is the answer
When temperature drops, (for example from 20 degrees celsius to 10 degrees celsius)
a.) energy increases
b.) particles move slower
c.) particles collide more often
d.) pressure increases
Answers
Answer:
In the Celsius scale each degree is one part of 100 degrees. This is because in this scale the difference between boiling and freezing temperatures of water is 100 ° - 0 ° = 100 °, so one degree Celsius is one part of 100.
In the Farhenheit scale, each degree is one part of 180 degrees. This is because in this scale the difference between the boiling and freezing temperatures are 212 ° - 32 ° = 180°, so one degree Fahrenheti is one part of 180.
That means that 1 °C is a larger amount than 1 °C, so 20°C is a larger amount than 20°F.
Conclusion: 20 degree change represents a larger change in Celsius scale.
Explanation:
In the Celsius scale each degree is one part of 100 degrees. This is because in this scale the difference between boiling and freezing temperatures of water is 100 ° - 0 ° = 100 °, so one degree Celsius is one part of 100.
In the Farhenheit scale, each degree is one part of 180 degrees. This is because in this scale the difference between the boiling and freezing temperatures are 212 ° - 32 ° = 180°, so one degree Fahrenheti is one part of 180.
That means that 1 °C is a larger amount than 1 °C, so 20°C is a larger amount than 20°F.
Conclusion: 20 degree change represents a larger change in Celsius scale.