Answer:
[tex]\boxed {\boxed {\sf 1.6 \times 10^{24} \ atoms \ Si}}[/tex]
Explanation:
We are asked to find how many atoms are in a sample of 75 grams of silicon.
1. Convert Grams to MolesFirst, we must convert grams to moles using the molar mass. This is the mass of 1 mole of a substance. The molar mass is found on the Periodic Table because it is equal to the atomic mass, but the units are grams per mole instead of atomic mass units.
Look up the molar mass of silicon.
Si: 28.085 g/molWe convert using dimensional analysis, so we must set up a conversion factor.
[tex]\frac {28.085 \ g \ Si}{1 \ mol \ Si}[/tex]
We are converting 75 grams of silicon to moles, so we multiply by this value.
[tex]75 \ g \ Si*\frac {28.085 \ g \ Si}{1 \ mol \ Si}[/tex]
Flip the conversion factor so the units of grams of silicon cancel.
[tex]75 \ g \ Si*\frac {1 \ mol \ Si}{28.085 \ g \ Si}[/tex]
[tex]75 *\frac {1 \ mol \ Si}{28.085 }[/tex]
[tex]\frac {75}{28.085} \ mol \ Si[/tex]
[tex]2.670464661 \ mol \ Si[/tex]
2. Convert Moles to AtomsNext, we convert moles to atoms using Avogadro's Number, or 6.022 ×10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. In this problem, the particles are atoms of silicon.
Set up another conversion factor, this time with Avogadro's Number.
[tex]\frac {6.022 \times 10^{23} \ atoms \ Si}{1 \ mol \ Si}[/tex]
Multiply by the number of moles we found.
[tex]2.670464661 \ mol \ Si*\frac {6.022 \times 10^{23} \ atoms \ Si}{1 \ mol \ Si}[/tex]
The units of moles of silicon cancel.
[tex]2.670464661 *\frac {6.022 \times 10^{23} \ atoms \ Si}{1 }[/tex]
[tex]2.670464661 * {6.022 \times 10^{23} \ atoms \ Si}[/tex]
[tex]1.60815382 \times 10^{24} \ atoms \ Si[/tex]
The original value of grams (75) has 2 significant figures, so our answer must have the same. For the number we found, that is the tenths place. The 0 in the hundredths place tells us to leave the 6 in the tenths place.
[tex]1.6 \times 10^{24} \ atoms \ Si[/tex]
Pa help po asap now na po
What is the mass of sulphate ions 96.06 in 25.0ml of a 0.125 solution
Answer:
12.34
Explanation:
because this is how we do this
Jason and Sheldon are neighbors who work for the same accounting firm. They leave the office at the same time. After t seconds, Jason's distance from the office in meters is given as 4 more than 3 times t, while Sheldon's distance from the office is 6 more than 2 times t.
The function that represents the total distance d(t) that Jason and Sheldon cover together in t seconds is given by d(t) =
. In 7 seconds, Jason and Sheldon together cover a distance of
meters.
Balance the equation
Ca(s) + H3PO4(aq) ---->Ca3(PO4)2(s) + H2(g)
Hey! Help please :)
Answer:
6. 15 oxygen atoms (The coefficient 5 is multiplied by the subscript 3 of oxygen)
7. The number "2" is the subscript.
Each of the following sets of quantum numbers is supposed
to specify an orbital. Which of the following sets of quantum
numbers contains an error?
A) n = 2, l = 1 , ml = -1
B) n = 4, l = 2, ml =0
C) n = 3, l =3 , ml = -2
D) n = 1, l = 0, ml =0
E) n = 3, l = 0, ml =0
Answer:
C
Explanation:
The azimuthal quantum number can take values from 0 to (n-1)
So in answer C n= 3, l can take values between 0
and 2.
l can't be 3.
ml can take values from -l to +l.
Hope you understood
(20 points) In the morning, you decide to make toasted bacon, lettuce, and tomato sandwich. Observe what happens in each stage of making the sandwich. Which parts involve only chemical changes happening?
I. The first thing you do is cut two slices of bread.
II. Then you put the slices in the toaster to cook. When the toaster is done, it pops the III. warm brown toast. You cook the bacon in a frying pan you put bacon, lettuce, and tomato on the bread, trimming the sides.
IV. You can smell the old bread in the garbage going moldy.
Steps I and II
Steps II and III
Steps II and IV
Steps III and IV
Answer:
C is the answer I did it and got it right
When the concentration of SO2(g) is increased to 1.48 M, the ratio of products to reactants is 1.4. The equilibrium constant for the reaction is 14. In which direction will the reaction shift to regain equilibrium
Answer:
Towards the products
Explanation:
The equilibrium constant for the reaction is 14. The equilibrium will shift towards the product.
What is equilibrium?Equilibrium is defined as a condition in which the forward and backward reaction rates are identical. When all of the external forces acting on an object are balanced, the object is said to be in equilibrium in a reference coordinate system. This indicates that all external forces and moments acting on this item have a net effect of zero.
When sulfur dioxide SO2 concentration is increased, the Q value rises to 1.4.
Q = [ SO₃ ]² / [ SO₂ ]² [ O₂ ]
Q = 1.4
Where K
K = [ SO₃ ]² / [ SO₂ ]² [ O₂ ]
K = 14
Q will shift to the right to consume the extra SO2 and restore the equilibrium position since Q is less than K.
Thus, the equilibrium constant for the reaction is 14. The equilibrium will shift towards the product.
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Explain how chemical spills on a person are handled when they are spilled :
(a) over the body
(b) in the eyes
How do weak intermolecular bond strengths affect the melting and boiling point of a substance? (Picture is of answers I can choose from)
For a weak intermolecular bond, both the melting point and boiling point are lower.
A lesser energy is required to break bond of weak intermolecular forces while a greater energy is required to break bond of strong intermolecular forces.
E ∝ T
where;
E is the energy required to break the bondT is the temperatureA lesser energy means a lower temperature and a lower temperature will result in lower boiling point and melting point.
Thus, we can conclude that for a weak intermolecular bond, both the melting point and boiling point are lower.
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PLEASE HELP
1. A closed bottle contains a mixture of Ar and O2 at 25.3°C. If the partial pressure of Ar in
the bottle is 0.447 atm and the total pressure of the bottle is 1.024 atm, what is the partial
pressure of O2 in the bottle?
Answer: 0.79 atm
Explanation:
The Ideal Gas Law is PV=nRT.
since both Ar and O2 have the same volume and temperature, the only variable causing the differnce in pressure betwwen the 2 gases is the number of moles
the total pressure = the partial pressure of Ar + the partial pressure of O2
1.024 atm = 0.447 amt + ?
so
? = 1.24 -0,447 = 1.24 - 0.45= 0.79 atmthe total pressure of the bottle is 1.024 atm, what is the partial
pressure of O2 in the bottle? is PV
(50 POINT) use this to answer: https://phet.colorado.edu/sims/html/acid-base-solutions/latest/acid-base-solutions_en.html
Describe how you could adjust the settings of the simulation to increase the number of red (H3O+) and blue (A-) particles in the solution of equilibrium. In three to four sentences, justify your answer and explain how and why this would change the pH of the solution.
The addition of more acid or base will increase the number of H3O+ and A- particles thereby decreasing and increasing the pH of the solution respectively.
What is an acid-base titration?An acid-base titration is one in which an acid is added to a given volume of base in order to neutralize it.
When more of acid is added to a solution of a base than is required to neutralize it, the solution becomes acidic.
Similarly, when more base is use to neutralize an acid than is required, the solution becomes alkaline.
In the given simulation, (H3O+) is the acid while (A-) is the base.
By adding increasing the quantity of acid added, the number of H3O+ particles will increase. This will reduce the pH of the solution.
Also, the adding more base to the solution, the number of A- particles in the solution will increase. This will increase the pH of the solution.
Therefore, addition of more acid or base will increase the number of H3O+ and A- particles thereby decreasing and increasing the pH of the solution respectively.
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PLEASE ANSWER WITHIN THIS HOUR!
Which of the following does NOT describe the epidermis?
A. It is waterproof.
B. It houses the sweat and oil glands.
C. It is the outermost layer of the skin.
D. Its surface consists of dead cells that continually shed off.
Thank you!
Answer:
it doesn't house the sweat and oil glands
Explanation:
the epidermis doesn't house the oil and sweat glands but the dermis does
What is vibration????
if 38 gr of water are produced in reaction, how many mole are CO2 are produced.
20 points! Please Help!!
Based on what you have read what is the opportunity cost of the glass-making company's decision?
a higher quaity tem
a greater proft
a loss of equipment
a longer production time
Answer:
a greater profit......
If acid comes in contact with your skin, why must you flush the area with plenty of cold water, rather than neutralizing the acid with a base?
Answer:
that would just create a bigger mess if you flush it with ice water it can reduce swelling and help dull your nerves
Explanation:
If acid comes in contact with your skin, because having an excessive amount of base can also be harmful. Acid is weakened and rendered ineffective by water.
What is acid?A chemical species known as an acid absorbs electrons and/or provides protons or hydrogen ions. When a hydrogen atom is bound to an acid, it can release (dissociate) and produce a cation as well as an anion in water. A substance's acidity and solution pH increase according to the amount of hydrogen ions it produces.
There are various definitions for acids. When someone uses the term "an acid," they typically mean an Arrhenius or Brnsted-Lowry acid. Often, a Lewis acid being referred to as a "Lewis acid." If acid comes in contact with your skin, because having an excessive amount of base can also be harmful. Acid is weakened and rendered ineffective by water.
Therefore, if acid comes in contact with your skin, because having an excessive amount of base can also be harmful. Acid is weakened and rendered ineffective by water.
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Bio fuel is a mixture of petrol and 20%——————
Answer:
methane and petrol okkkkkkkkkkkkkkkkkkk
1) When a beam of white rays is dispersed by a prism which colour will be refracted to a larger extent?
Explanation:
since diferentes colours of light través at diferentes speeds, the refractiva index is diferentes for each color. The result? that whenthe White light países thought the prism it cover into a red light
help me. correct answer will be marked as brnlst
Answer:
PCI3
Explanation:
It does not obey the octet rule on the nitrogen atom.
A chemical reaction occurs when _________.
A. Chemical Bonds are build
B. A new substance is created
C. Chemical Bonds are broken
D. All of the Above
Answer:
C. Chemical Bonds are broken
Explanation:
A chemical reaction occurs when chemical bonds are broken.
Chemical reactions occur when chemical bonds between atoms are formed or broken.
Hope this helps :)
Answer:
c: chemical bonds are broken
Explanation:
the broken bonds then create new bonds, rearranging the atoms into a new substance :)
Write and balance the equation for the complete combustion of heptane, C7H16. Phase symbols and energy changes are optional.
The balanced equation for the complete combustion of heptane, [tex]C_{7}H_{16}[/tex] is given as,
[tex]C_{7}H16(g) + 11O_{2} (g)[/tex] → [tex]7CO_{2}(g) + 8H_{2}O(g)[/tex] + heat/light
What is combustion reaction?It is exothermic redox chemical reaction.The reaction between fuel and oxidant to produce oxidized product is called combustion reaction.The oxidant are usually atmospheric oxygen.The oxidized product is carbon dioxide gas and water.What is balanced chemical equation?The chemical equation in which number of atom each elements is equal in reactant and product of the reaction is called balanced chemical equation.
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How does using more water in a beaker affect the solubility in an experiment?
Answer:
it may lead to read false measurements
while in an experiment.
that's what I think.
Certain __________ metals like gold are found as pure metals rather than ores in the earth. Complete the sentence.
Answer:
nonreactive
Explanation:
Why were people from lower castes drawn to Buddhism?
O The Buddhist belief in equality appealed to them.
O Buddhism allowed people from all castes to participate.
People from the lower castes were born into Buddhism.
O People in the lower castes wanted to choose their own religi
Answer:
During the Maurya empire, the Indian culture and way of life were deeply influenced by Buddhism. Buddhism appealed to people of lower castes because it emphasized individuals' path to enlightenment and salvation, which could be attained in this life.
Explanation:
What is the name of the branched alkane shown below?
لہ
A. 3-methyloctane
B. 4-methylheptane
C. 3-methylheptane
D. 4-methyloctane
Answer:
4-methyloctane
Explanation:
other guy got it wrong, this one's right
The name of the branched alkane is 4-methyloctane as it has 8 carbon atoms.
What is an atom?An atom is defined as the smallest pa of matter which makes a basis of an element. Every form of matter whether it be a solid,liquid , gas consists of atoms . Each atom has a nucleus which is contains protons and neutrons and shells in which the electrons revolve.
The protons are positively charged particles and neutrons are neutral particles and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged particles and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not change the chemical properties of the substances.
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An aqueous solution of a vanadium chloride salt is electrolyzed by a current of 3.00 A passing through the solution for 60.0 min. If 5.70 g of vanadium is produced at the cathode during this time, what is the likely formula unit for the vanadium salt
From the information in the question, the formula unit of the salt is given as VCl.
The quantity of charge produced is obtained from;
Q = It
I = current (3 A), t = time (3600 s)
Q = 3 A × 3600 s
Q = 10800 C
Now we need to find the number of electrons transferred as follows;
51 g of Vanadium is deposited by 96500n C
5.70 g is deposited by 10800 C
5.70 × 96500n = 51 × 10800
n = 51 × 10800/5.70 × 96500
n = 1
The formula of the salt is VCl.
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What type of mixture is this illustration?
Answer:
Suspension
Explanation:
It's a suspension because it is not mixed at all, and has distinctly separate layers.
Two students are identifying a sample of tap water.
Student A says that tap water is a mixture, while
Student B says that it is a compound. Which student
is correct? Justify your answer.
Tap water is a mixture not compound due to presence of many substance.
Tap water is an example of mixture not compound because in tap water, water is not available in pure form, it has many substances mix with water and those substances make no bond with water.
It has dissolved compounds like calcium carbonate, magnesium and fluoride. Different elements or compounds are physically combined rather than chemically linked together so we can conclude that student A is correct that tap water is a mixture.
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*1. Which statement about the temperature of a phase changes in electrostatic forces holding the molecules is correct?
A. The temperatures of which a substance changes phases is dependent of the size of the molecules in the substance.
B. The strength of the forces between molecules in a substance depends on the number of filled electron shells.
C. The temperatures at which a substance changes phases indicate the relative strength of the forces between molecules in the substance.
D. The strength of the forces between molecules in a substance is the strongest at higher temperatures.
•
•
•
*2. Which list shows the phases of matter in order from strongest collective electrostatic forces to weakest collective electrostatic forces?
A. Gas, solid, liquid
B. Gas, liquid, solid
C. Liquid, solid gas
D. Solid, liquid, gas
•
•
•
*3. Which change happens when water boils?
A. The forces between water molecules become stronger, and the bonds between atoms in the water remain unchanged.
B. The forces between water molecules are unchanged, and the bonds between the atoms in a water break.
C. The force is between water molecules in the bonds between the atoms in the water molecules break.
D. The forces between water molecules break, and the bonds between the atoms in water are unchanged.
•
•
•
*4. A sample of calcium carbonate is cooled. Which change happens to the molecules of calcium carbonate in the sample?
A. The forces weaken, and the molecules move around.
B. The molecules break apart and then form stronger forces.
C. The forces strengthen, and the molecule structure becomes more rigid.
D. The molecules vibrate more and weaken the forces.
•
•
•
*5. The boiling point of acetone is lower than the boiling point of ethanol. Based on this information, which conclusion can be drawn about the two substances?
A. The intramolecular bonds in acetone are stronger than the intramolecular bonds in ethanol.
B. The intermolecular forces in ethanol are stronger than the intermolecular forces in acetone.
C. The intramolecular bonds in ethanol are stronger than the intramolecular bonds in acetone.
D. The intermolecular forces in acetone are stronger than the intermolecular forces in ethanol.
Answer:
see below
Explanation:
1. The temperatures at which a substance changes phases indicate the relative strength of the forces between molecules in the substance.
2. solid, liquid, gas
3. The forces between water molecules break, and the bonds between the atoms in water are unchanged.
4. The forces strengthen, and the molecule structure becomes more rigid.
5. The intermolecular forces in ethanol are stronger than the intermolecular forces in acetone.
The the degree of intermolecular interaction between molecules determines the magnitude of boiling point of the substance.
During phase change, a substance moves from one state of matter to another. The temperature at which a phase change occurs is determined by the strength of the forces between molecules in the substance. The relative magnitude of intermolecular forces between molecules in different states of matter is solids > liquids > gases.
During boiling, energy is imparted to the molecules of a liquid. When this occurs, the forces between water molecules break, and the bonds between the atoms in water are unchanged.
We must recall that the molecules of a substance are in constant random motion. The average kinetic energy of molecules is proportional to temperature. As a sample of calcium carbonate is cooled, the forces between molecules strengthen, and the molecule structure becomes more rigid.
The magnitude of intermolecular interaction affects the boiling point of a liquid. The stronger the magnitude of intermolecular interaction,the higher the boiling point. As such, ethanol having hydrogen bonds between its molecules has a higher boiling point than acetone which only posses weaker dipole - dipole interactions.
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