The question is incomplete, the complete question is;
Silicon has three naturally occurring isotopes with thefollowing masses and natural abundances:
Isotope Mass ({\rm amu}) Abundance (%)
{\rm Si}-28 27.9769 92.2
{\rm Si}-29 28.9765 4.67
{\rm Si}-30 29.9737 3.10
Calculate the atomic mass of silicon.
Answer:
28.09 amu (to four significant figures)
Explanation:
Given that;
Isotope Mass Abundance (%)
Si-28 27.9769 92.2
Si-29 28.9765 4.67
Si-30 29.9737 3.10
So we now have;
Relative atomic mass of silicon;
(27.9769 × 0.9218) + (28.9765 × 0.0471) + (29.9738 × 0.0312)
25.789 + 1.365 + 0.9351 = 28.09 amu (to four significant figures)
What is CaF2(aq) + Rb
Answer:
RbF2 + Ca
Explanation:
Since Rb is located in IIA as well as Ca, Rb has ion form Rb2+
Hence CaF2 + Rb → RbF2 +Ca
Please be reminded, this answer may not be 100% correct
Based on the molecular formula, determine whether each of the following is an alkane, alkene, or alkyne. (Assume that the hydrocarbons are noncyclical and there is no more than one multiple bond.)
a. C3H6
b. C6H12
c. H8H18
d. C7H12
Answer:
C₃H₆ is an alkene
C₆H₁₂ is an alkene
C₈H₁₈ is an alkane
C₇H₁₂ is an alkyne
Explanation:
To determine which of the compound is alkane, alkene, or alkyne,we shall use the general formula of alkane, alkene, and alkyne. This is illustrated below:
General formula for alkane => CₙH₂ₙ₊₂
General formula for alkene => CₙH₂ₙ
General formula for alkyne => CₙH₂ₙ₋₂
For C₃H₆:
n = 3
Alkane => CₙH₂ₙ₊₂ => C₃H₂₍₃₎₊₂ => C₃H₈
Alkene => CₙH₂ₙ => C₃H₂₍₃₎ => C₃H₆
Alkyne => CₙH₂ₙ₋₂ => C₃H₂₍₃₎₋₂ => C₃H₄
Thus, C₃H₆ is an alkene
For C₆H₁₂:
n = 6
Alkane => CₙH₂ₙ₊₂ => C₆H₂₍₆₎₊₂ =>C₆H₁₄
Alkene => CₙH₂ₙ => C₆H₂₍₆₎ => C₆H₁₂
Alkyne => CₙH₂ₙ₋₂ => C₆H₂₍₆₎₋₂ => C₆H₁₀
Thus, C₆H₁₂ is an alkene
For C₈H₁₈:
n = 8
Alkane => CₙH₂ₙ₊₂ => C₈H₂₍₈₎₊₂ => C₈H₁₈
Alkene => CₙH₂ₙ => C₈H₂₍₈₎ => C₈H₁₆
Alkyne => CₙH₂ₙ₋₂ => C₈H₂₍₈₎₋₂ => C₈H₁₄
Thus, C₈H₁₈ is an alkane.
For C₇H₁₂:
n = 7
Alkane => CₙH₂ₙ₊₂ => C₇H₂₍₇₎₊₂ => C₇H₁₆
Alkene => CₙH₂ₙ => C₇H₂₍₇₎ => C₇H₁₄
Alkyne => CₙH₂ₙ₋₂ => C₇H₂₍₇₎₋₂ => C₇H₁₂
Thus, C₇H₁₂ is an alkyne.
SUMMARY:
C₃H₆ is an alkene
C₆H₁₂ is an alkene
C₈H₁₈ is an alkane
C₇H₁₂ is an alkyne
Marine chemist exam in the mass percent composition of manganese sulfide compound from ocean floor he determined that 60.2% of this compound is sulfur determine the mole ratio between manganese and sulfur
Explanation:
Let the mass of the compound be 100g.
There are 60.2g of sulfur.
Moles of sulfur
= 60.2g / (32.07g/mol) = 1.877mol
There are 100g - 60.2g
= 39.8g of manganese.
Moles of manganese
= 39.8g / (54.94g/mol) = 0.724mol
Mole ratio of manganese to sulfur
= 0.724mol : 1.877mol = 1 : 2.5.
BRAINLLEST! Boiling water for mac and cheese is a physical change. Give 2 pieces of evidence to support this claim
Answer:
In explanation.
Explanation:
Physical changes are generally changes in states of matter. So, the water going from liquid to gas is a phase change and therefore physical. (It's still water, just in a different form). Im not sure about the second piece of evidence though. Unless you are talking about the Mac and Cheese which in that case is also a physical change as the two ingredients cheese and macaroni stay the same when cooked just become softer and edible.
describe the difference between a physical and chemical change explain what happens during a checmical reaction
Explanation:
A physical change is a change that alters the physical properties of matter particularly the form and state.
In many cases the change is easily reversible. Examples are changes of state such as freezing, boiling, melting e.t.c
A chemical change is a change in which a new kind of matter is formed. It is always accompanied by energy changes which can either be evolution or absorption of heat or light or both.
The process is not easily reversible. Examples are combustion, rusting of iron, precipitation, e.t.c
During a chemical reaction, the reactants undergo a chemical change.
How do I round 74,000 to have only one significant figure?
Answer:
7x10⁴.
Explanation:
Hello!
In this case, when rounding big number to a representation with less significant figures than it, we need to make sure we remove the spare figures and round up whether the next digit is five or more.
In such a way, for 74,000, we notice that 4 is not enough to round up the 7, that is why the number would contain a 7 only; moreover, to get rid of the thousand places, we need to introduce an exponent in 4 places, which means that the result would be:
7x10⁴.
Best regards!
Identify the good electrical conductor. Carbon Copper Nitrogen Sulfur
A chemist prepares a solution of silver (I) perchlorate (AgCIO4) by measuring out 134.g of silver (I) perchlorate into a 50.ml volumetric flask and filling the flask to the mark with water. calculate the concentration in mol/L of the silver (I) perchlorate soluation
Answer:
13 M
Explanation:
Molar mass of AgCIO4 = 207 g/mol
Number of moles of AgCIO4= 134/207= 0.65 moles
Number of moles= concentration × volume
Concentration = number of moles/volume
Concentration = 0.65 × 1000/50 = 13 M
What is the coefficient, subscript for V, and subscript for O in V2O5
Answer: Coefficient 0
subscript for V 2
subscript for O 5
Explanation: yes
There is no coefficient in V₂O₅ and the subscript of vanadium V is 2 and the subscript of oxygen is 5.
What is vanadium pentoxide ?Vanadium pentoxide is an ionic compound formed by donating electrons from the vanadium metal to oxygen. The chemical formula of vanadium pentoxide is V₂O₅.
The chemical formula of a compound is written in terms of the chemical symbol of each constituent elements and the number of their atoms. The number of atoms is written as subscript for the chemical symbols.
In V₂O₅, there are are 2 vanadium atoms and 5 oxygen atoms. Coefficients are numbers prior to the formula in reaction. Here there is no coefficient and the subscript for V is 2 and that of O is 5.
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If the symbol X represents a central atom, Y represents outer atoms, and Z represents lone pairs on the central atom, the structure Y---:X:------Y could be abbreviated as XY2Z2.Classify these structures by the hybridization of the central atom. XY4Z2, XY4Z, XY5Z, XY2Z3, XY2Z, XY3Z, XY2Z2, XY3Z2,XY2,XY3,XY4,XY5,XY6
Answer:
XY4Z2- dsp2
XY4Z- sp3d
XY5Z- sp3d2
XY2Z3- sp3d
XY2Z- sp2
XY3Z- sp3
XY2Z2- sp3
XY3Z2- sp3d
XY2 - sp
,XY3- sp2
XY4- sp3
,XY5- sp3d
XY6- sp3d2
Explanation:
In the answer box I have shown the hybridization patterns of the various arrangement of bond pairs and lone pairs.
Hybridization was put forward to explain the shapes of molecules under the valence bond theory. All molecules having the same hybridization pattern are based on the same geometry. Deviations from the expected geometry may arise due to the presence of lone pairs.
Which macromolecules break apart by hydrolysis?
Answer:
Dehydration synthesis reactions build molecules up and generally require energy, while hydrolysis reactions break molecules down and generally release energy. Carbohydrates, proteins, and nucleic acids are built up and broken down via these types of reactions, although the monomers involved are different in each case.
Explanation:
A nucleus with four protons has total positive charge
A 0.4647-g sample of a compound known to contain only carbon, hydrogen, and oxygen was burned in oxygen to yield 0.8635 g of CO2 and 0.1767 g of H2O. What is the empirical formula of the compound?
Answer: The empirical formula is [tex]C_3H_3O_2[/tex].
Explanation:
The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:
[tex]C_xH_yO_z+O_2\rightarrow CO_2+H_2O[/tex]
where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.
We are given:
Mass of [tex]CO_2[/tex] = 0.8635
Mass of [tex]H_2O[/tex]= 0.1767 g
Molar mass of carbon dioxide = 44 g/mol
Molar mass of water = 18 g/mol
For calculating the mass of carbon:
In 44g of carbon dioxide, 12 g of carbon is contained.
So, in 0.8635 g of carbon dioxide, =[tex]\frac{12}{44}\times 0.8635=0.2355g[/tex] of carbon will be contained.
For calculating the mass of hydrogen:
In 18g of water, 2 g of hydrogen is contained.
So, in 0.1767 g of water, =[tex]\frac{2}{18}\times 0.1767=0.0196g[/tex] of hydrogen will be contained.
Mass of oxygen in the compound = (0.4647) - (0.2355+0.0196) = 0.2096 g
Mass of C = 0.2355 g
Mass of H = 0.0196 g
Step 1 : convert given masses into moles.
Moles of C =[tex] \frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{0.2355g}{12g/mole}=0.0196moles[/tex]
Moles of H=[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.0196g}{1g/mole}=0.0196moles[/tex]
Moles of O=[tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{0.2096g}{16g/mole}=0.0131moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C =[tex]\frac{0.0196}{0.0131}=1.5[/tex]
For H =[tex]\frac{0.0196}{0.0131}=1.5[/tex]
For O = [tex]\frac{0.0131}{0.0131}=1[/tex]
The ratio of C : H: O = 1.5 : 1 .5 : 1
Converting to simple whole number ratio:
The ratio of C : H: O = 3 : 3: 2
Hence the empirical formula is [tex]C_3H_3O_2[/tex].
(9) How many moles of oleum in 1780. g of oleum? - Write an equation to summarize the process.
Answer:
1. 10moles
2. Find the summarized equation below
Explanation:
Mole = mass ÷ molar mass
Molar mass of oleum (H2S2O7) = 1(2) + 32(2) + 16(7)
= 2 + 64 + 112
= 178g/mol
According to the information provided, the mass of oleum is 1780g, hence, the number of moles in it is:
Mole = 1780/178
Mole = 10moles
2. The summarized equation of the contact process is:
1) S + O2 → SO2
2) 2SO2 + O2 → 2SO3
3) SO3 + H2SO4 (conc. sulfuric acid) → H2S2O7
4) H2S2O7 + H2O → 2H2SO4 (dilute sulfuric acid)
What is the molar mass of Mg(CIO3)2
The following graph shows a decay chain. Which part of the decay chain will take the most time?
Tim and Jose are moving furniture. Tim pushes a 150 kg sofa with 300N
force. As a result, Sofa’s acceleration was __________ according to Newton’s
Second Law of motion. (F = ma)
Answer:
a = 2m/s²
Explanation:
Given data:
Mass of sofa = 150 Kg
Force applied = 300 N
Acceleration = ?
Solution:
Formula:
F = ma
F = force
m = mass
a = acceleration
by putting values,
300 N = 150 Kg × a
a = 300 N /150 Kg
a = 300 Kg m/s² / 150 Kg ( N = Kgm/s²)
a = 2m/s²
how an object accelerates when it changes direction?
Answer:
An object which experiences either a change in the magnitude or the direction of the velocity vector can be said to be accelerating. This explains why an object moving in a circle at constant speed can be said to accelerate - the direction of the velocity changes.
Explanation:
Answer:
An object which experiences either a change in the magnitude.
Explanation:
the direction of the velocity changes.
Hope that helps :)
Have a good day
Which of the following best explains why Reggie's books fell?
Explanation:
When Reggie's car turned eastward, his books continued heading northward, causing them to slide off the top of his car and fall.
were is the opshons.
The element in Period 4 and Group 14 of the Periodic Table would be classified as a
Answer:
Chalcogen
Explanation:
A sample of iron is put into a calorimeter (see sketch at right) that contains of water. The iron sample starts off at and the temperature of the water starts off at . When the temperature of the water stops changing it's . The pressure remains constant at . Calculate the specific heat capacity of iron according to this experiment. Be sure your answer is rounded to the correct number of significant digits.
Answer:
Therefore, the specific heat capacity of the iron is 0.567J/g.°C.
Note: The question is incomplete. The complete question is given as follows:
A 59.1 g sample of iron is put into a calorimeter (see sketch attached) that contains 100.0 g of water. The iron sample starts off at 85.0 °C and the temperature of the water starts off at 23.0 °C. When the temperature of the water stops changing it's 27.6 °C. The pressure remains constant at 1 atm.
Calculate the specific heat capacity of iron according to this experiment. Be sure your answer is rounded to the correct number of significant digits
Explanation:
Using the formula of heat, Q = mc∆T
where Q = heat energy (Joules, J), m = mass of a substance (g)
c = specific heat capacity (J/g∙°C), ∆T = change in temperature (°C)
When the hot iron is placed in the water, the temperature of the iron and water attains equilibrium when the temperature stops changing at 27.6 °C. Since it is assumed that heat exchange occurs only between the iron metal and water; Heat lost by Iron = Heat gained by water
mass of iron = 59.1 g, c = ?, Tinitial = 85.0 °C, Tfinal = 27.6 °C
∆T = 85.0 °C - 27.6 °C = 57.4 °C
mass of water = 100.0 g, c = 4.184 J/g∙°C, Tinitial = 23.0 °C, Tfinal = 27.6 °C
∆T = 27.6°C - 23.0°C = 4.6 °C
Substituting the values above in the equation; Heat lost by Iron = Heat gained by water
59.1 g * c * 57.4 °C = 100.0 g * 4.184 J/g.°C * 4.6 °C
c = 0.567 J/g.°C
Therefore, the specific heat capacity of the iron is 0.567 J/g.°C.
6- A favorable condition for two elements to form an ionic bond is?
a- both should be electronegative
b- one should have low electron affinity and the other low ionization energy.
C- one should have high electron affinity and the other low ionization energy.
d- both should be highly electronegative
Answer: C- one should have high electron affinity and the other low ionization energy.
Explanation:
Ionization energy is the energy required to remove the electron from an isolated gaseous atom.
Electron affinity is the tendency of an isolated atom to attrcat the electrons towards itsellf.
An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element or the metal and it can donate electron easily if it has low ionization energy.
The element which accepts the electrons is known as electronegative element or non metal and it can easily accept the electron if it has high electron affinity.
What is the formula for the ionic compound formed between sodium and oxygen?
Answer:
Na2O (the 2 is small the o is not a 0 but and OOh)
Explanation:
Hey there, The formula for the compound formed between sodium and oxygen will be Na2O
Though since sodium is a metal and oxygen is a nonmetal, Na2O is expected to be ionic.
What is an ionic compound?An ionic compound is a chemical compound made up of ions held together by electrostatic forces known as ionic bonding.
To determine an ionic compound's formula, first identify the cation and record its symbol and charge.
After that, identify the anion and record its symbol and charge. Finally, mix the two ions together to make an electrically neutral compound.
After two or more atoms lose or gain electrons to form an ion, an ionic bond can form.
Ionic bonds form when metals lose electrons and nonmetals gain electrons. Ions with opposite charges attract each other, forming an ionic bond.
The symbol for sodium is Na+, and the symbol for oxygen is O2. The resulting compound here in the given condition is Na2O.
Thus, this is the formula for the ionic compound formed between sodium and oxygen.
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How many sulfur atoms are in 5 SF6 ?
Answer:
The molecular formula for sulfur hexafluoride is SF6 S F 6 , in which there is 1 sulfur atom and 6 fluorine atoms.
Explanation:
hope this helps
aqueous hydrochloric acid HCl will react with solid sodium hydroxide NaOH to produce aqueous sodium chloride NaCl and liquid water H2O. Supposed 6.93 g of hydrochloric acid is mixed with 2.4 g of sodium hydroxide. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 2 significant digits. g
Answer:
Explanation:
HCl + NaOH = NaCl + H₂O.
1 mole 1 mole 1 mole 1 mole
6.93 g of hydrochloric acid = 6.93 / 36.5 = .189 mole of HCl
2.4 g of NaOH = 2.4 / 40 = .06 mole of NaOH
NaOH is in short supply so it is the limiting reagent .
1 mole of NaOH reacts with 1 mole of HCl to give 1 mole of Water
.06 mole of NaOH will react with .06 mole of HCl to give .06 mole of water
Water formed = .06 mole
= .06 x 18 = 1.08 g
= 1.1 g
What type of weather typically results from a low pressure system?
I need help!!!!
Answer:
Storms and hurricanes can be formed with low pressure. It always results into unsettled weather.
Explanation:
Hope this helps!
Dribbling a basketball harder into the floor makes it bounce higher is an example of what newton's law?
What is ATP? How does it provide energy
According to Image 2, which tectonic plate is composed of the largest percentage of oceanic lithosphere?
A. African Plate
B. Eurasian Plate
C. Indian Plate
D. Nazca Plate
Answer:
I think the answer is A the Afracan plate
Explanation:
hope this helps:)
Jill graphs the speed of a model train that is travelling at a speed of 15 kilometers per hour. Which graph shows the speed of the model train?
Answer:c
Explanation: