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]
I will give brainlist
How much Ba(OH)2, in grams, is needed to make a 1.00m aqueous solution?
Answer:
We can say that we need 171 g barium hydroxide needed to make one model equals solution.
Explanation:
I hope this answered your question.
171 gram of Ba(OH)2, in grams, is needed to make a 1.00 m aqueous solution.
What is mass?Mass is the quantity of matter. The mass is calculated by the density divide by the volume.
In 1.00 solution, the mass of Ba(OH)2 is 171 gram.
Thus, the mass of Ba(OH)2 is 171 gram.
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How are sound and light similar? How are they different?
Answer:
Sound requires a medium to move through; light does not.
Sound and light are similar in that both are forms of energy that travel in waves.
Explanation:
Sound and light are similar in that both are forms of energy that travel in waves. They both have properties of wavelength, freqency and amplitude. Sound can only travel through a medium (substance) while light can travel through empty space. Sound is a form of mechanical energy caused by vibrations of matter.
Light waves DO NOT require a medium, they travel fastest in empty space; Sound waves REQUIRE a medium, they travel fastest in dense material like solids. Sound is a longitudinal wave.
How are metals, metalloids, nonmetals grouped
no I will not please put you because that's the god of the Bible
Metals are good conductors of heat and electricity, and are malleable (they can be hammered into sheets) and ductile (they can be drawn into wire).
Nonmetals are (usually) poor conductors of heat and electricity, and are not malleable or ductile; many of the elemental nonmetals are gases at room temperature, while others are liquids and others are solids.
The metalloids are intermediate in their properties. In their physical properties, they are more like the nonmetals, but under certain circumstances, several of them can be made to conduct electricity.
hope this answer helped u, if u can pls mark me as the brainliest. :)
Assume that the heat lost by the surface is gained by ethyl chloride. What enthalpies must you consider if you were to calculate the final temperature of the surface
Answer:
Specific heat of ethyl chloride in gas and liquid phases, enthalpy of vaporization and specific heat of solid surface.
Explanation:
In order to determine the final temperature, the heat lost by the chloride needs to be found. This would require the specific heat in both phases and the enthalpy of vaporization. (you will use q=mc(delta)T and q=m(delta)H)
Then the energy gained by the surface needs to be found. This will require the specific heat in order to use the q=mc(delta)T equation.
The enthalpies that we consider to calculate the final temperature of the surface are Specific heat of surface and ethyl chloride as well as Heat of vaporization of liquid & vapor ethyl chloride.
What is enthalpy?Enthalpy of any reaction tells about the total amount of heat absrobed and released during a chemical reaction.
According to the question, heat released by the surface is absorbed by the ethyl chloride and by absorbing this energy ethyl chlorode will change into the vapor form. In the whole process if we want ot calculate the final temperature on the surface then we should consider:
Specific heat of surface.Specific heat of ethyl chloride.Heat of vaporization of liquid ethyl chloride.Heat of vaporization of vapor ethyl chlorideHence, required enthalpies are Specific heat of surface and ethyl chloride as well as Heat of vaporization of liquid & vapor ethyl chloride.
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Potassium metal reacts with water according to the following balanced equation.
2 K(s) + 2 H2O(l) — 2 KOH(aq) + H, (8)
If one mole of potassium reacts in this manner, how many moles of water are consumed?
Answer: 1 mole
Explanation:
One mole reacts because there is a 1:1 ratio between the potassium and water at the beginning of the equation. 2K+2H2O has a 1 to 1 ratio. If one potassium reacts there is one h2o that also reacts.
Taking into account the reaction stoichiometry, if one mole of potassium reacts, 1 mole of water are consumed.
Reaction stoichiometryIn first place, the balanced reaction is:
2 K + 2 H₂O → 2 KOH + H₂
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
K: 2 moles H₂O: 2 moles KOH: 2 moles H₂: 1 moleMoles of water consumedThe amount of water consumed is calculated from the following rule of three: if by stoichiometry 2 moles of K react with 2 moles of H₂O, 1 mole of K react with how many moles of H₂O?
[tex]amount of moles of H_{2} O=\frac{1 mole of Kx2 moles ofH_{2} O }{2 moles of K}[/tex]
amount of moles of H₂O= 1 mole
In summary, if one mole of potassium reacts, 1 mole of water are consumed.
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identify key concept/terminologies about solution or concentration of solution?
pls help me
thanks~
Answer :
[tex] \: [/tex]
Concentration of Solutions
Recall that a solution consists of two components: solute (the dissolved material) and solvent (the liquid in which the solute is dissolved). The amount of solute in a given amount of solution or solvent is known as the concentration. The two most common ways of expressing concentration are molarity and molality.
Molarity
The molar concentration (M) of a solution is defined as the number of moles of solute (n) per liter of solution (i.e, the volume, V solution):
M = n / V solution
The units of molarity are mol/L, often abbreviated as M.
For example, the number of moles of NaCl in 0.123L of a 1.00M solution of NaCl can be calculated as follows:
[tex]0.123 \: l \: \: of \: solution \: \times \: \frac{1.00 \: mole}{1.00 \: l \: of \: solution \: } \: \\ = 0.123 \: moles[/tex]
Molality :
The molal concentration (m) of a solution is defined as the number of moles of solute (n) per kilogram of solvent (i.e., the mass of the solvent, msolvent):
[tex]m = \frac{n}{v \: solution} [/tex]
For example, the number of moles of NaCl dissolved in 0.123kg of H2O (the solvent), in order to make a 1.00m solution of NaCl, can be calculated as follows:
[tex]0.123 \: kg \: of \: solvent \: = \frac{1.00 \: mole}{1.00 \: kg \: of \: solvent \: } \\ = 0.123 \: moles[/tex]
Place the events of a fight or flight situation in the correct order.
Question 3 options:
You spring into action
Your heart and lungs prepare to fight or run
You see the bear
Your brain sends signals to you adrenal and pituitary glands
Answer:
you see le bear
you brain sends signals
your heart and lungs receive said signals
spring to action
Stems are important plant structures because they _________.
A.
are the main sites of photosynthesis for plants
B.
are the only site of water and nutrient transport
C.
allow plants to absorb water and nutrients from the soil
D.
give the plant structure and support
Answer:
c
Explanation:
allow plants to absorb water and nutrients from the soil
Do you think sugar would be soluble in hexane based on its structure
Answer:
The dipole forces (particularly H-bonds) that keep polar solute molecules together can be replaced by polar solute-solvent interactions, so substances that are predominantly polar (like glucose) dissolve in polar solvents like water but not in nonpolar solvents like hexane (H-bonds).
Explanation:
What is inertia?(1 point)
A. a force that acts on an object at rest
B. the motion of an object
C. an object’s resistance to a change its motion
D. the speed and direction of an object in motion
Answer:
I think it's C. hope this helps:)
What equipment is generally used to make lyophilized medications suitable for administering to the patient? a) Test tubes or sterile ampules b) Petri dishes and sterile droppers c) Sterile syringes or graduated cylinders d) Measuring cups and clean, warm water
Answer:
The answer is B
B = Petri dishes and sterile droppers
Explanation:
How many atoms are in mercury phosphate
Answer:
There are 95 atoms in mercury phosphate
Explanation:
You just add the atomic number for both elements
Identify the general features of an amino acid. Which part is responsible for the unique properties of each amino acid
Answer:
Every amino acid also has another atom or group of atoms bonded to the central atom known as the R group. This R group, or side chain, gives each amino acid proteins specific characteristics, including size, polarity, and pH.
Explanation:
The R group is another atom or group of atoms that is attached to the core atom in every amino acid. This R group, or side chain, provides each amino acid protein with unique properties such as size, polarity, and pH.
Amino acids are chemical molecules that are used to construct proteins. Proteins are vital macromolecules in living organisms, serving a variety of functions including enzymatic catalysis, structural support, transportation, immunological response, and others. A polypeptide chain is formed by linking amino acids in a precise sequence, which subsequently folds into a three-dimensional structure to make a functioning protein.
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A solution is prepared by dissolving 15.0 g of pure HC2H3O2 and 25.0 g of NaC2H3O2 in 775 mL of solution (the final volume). Incorrect answer icon Incorrect. Did you use the correct form of the H-H equation
The heat of combustion of propane, C3H8 (g) is -2057 kJ/mol. What would be the enthalpy change if enough propane was burned to give off 12 moles of carbon dioxide gas
Considering the reaction stoichiometry, the enthalpy change if enough propane was burned to give off 12 moles of carbon dioxide gas is 8228 kJ.
The balanced reaction is:
C₃H₈(g) + 5 O₂(g) → 3 CO₂(g) + 4 H₂O(l)
The heat of combustion of propane, C₃H₈, is -2057 kJ/mol. This is, 2057 kJ is released for every 1 mol C₃H₈.
So to determine the enthalpy change if enough propane was burned to emit 12 moles of carbon dioxide, you must take into account the stoichiometry of the reaction.
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
C₃H₈: 1 mole O₂: 5 moles CO₂: 3 moles H₂O: 4 molesThen you can apply the following rule of three: if by stoichiometry 3 moles of CO₂ are produced by 1 mole of C₃H₈, 12 moles of CO₂ are produced by how many moles of C₃H₈?
[tex]amount of moles of C_{3} H_{8} =\frac{12 moles of CO_{2}x1 mole of C_{3} H_{8} }{3 moles of CO_{2}}[/tex]
amount of moles of C₃H₈= 4 moles
So to determine the enthalpy change, you can apply the following rule of three: If for each mole of C₃H₈ 2057 kJ are released, for 4 moles of C₃H₈ how much heat is released?
[tex]Heat released=\frac{4 molesx2057 kJ}{1 mole}[/tex]
Heat released= 8228 kJ
The enthalpy change if enough propane was burned to give off 12 moles of carbon dioxide gas is 8228 kJ.
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https://brainly.com/question/10936616?referrer=searchResultsbrainly.com/question/16487206?referrer=searchResults brainly.com/question/14446695?referrer=searchResults brainly.com/question/11564309?referrer=searchResults brainly.com/question/4025026?referrer=searchResults brainly.com/question/18650135?referrer=searchResultsWhich of the following solutions represents a good buffer system? a solution that is 0.10 mol L-1 NaOH and 0.10 mol L-1 KOH a solution that is 0.10 mol L-1 HCl and 0.10 mol L-1 NH4+ a solution that is 0.10 mol L-1 HF and 0.10 mol L-1 CH3COONa a solution that is 0.10 mol L-1 HCl and 0.10 mol L-1 KCl a solution that is 0.10 mol L-1 CH3COOH and 0.10 mol L-1 CH3COOLi
Answer:
chu papi
Explanation:
if 38 gr of water are produced in reaction, how many mole are CO2 are produced.
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
I. Indicate whether the following statements are true or false 1. The entropy of a fixed amount of an incompressible substance increases in every process for which temperature increase. A: True B: False 2. A closed system can experience a decrease in entropy only when there is heat transfer from the system to its surroundings during the process. A: True B: False 3. Entropy is produced in every internally reversible process of a closed system. A: True B: False 4. In an adiabatic and internally reversible process of a closed system the entropy remains constant A: True B: False 5. The entropy of a fixed amount of an ideal gas increases in every isothermal process A: True B: False 6. The energy of an isolated system must remain constant, but the entropy can only decrease A: True B: False 7. The entropy change of a closed system during a process can be greater than, equal to, or less than zero. A: True B: False
A gas has a volume of 1140 ml at 37 ºC and 620 mm Hg pressure. Calculate its volume at STP.
1.900
2.800
3.819
4.1000
Answer:
3. 0.819L (819 mL)
Explanation: Before we go about solving this, we need to do some conversions prior to using the gas law, the gas law is as follows...
P(atm)*V(L)=n(mol)*r(constant)*T(in kelvin)
So here are all the conversions you need.
620 mm Hg -> 0.816 atm
1140 mL -> 1.14 L
37 C -> 310.15 K
After plugging in our new converted values, we will proceed to solve the number of moles of the gas present, our n value, so our equation will look like this...(Note: Constant r in this case is 0.08206 L*atm/K*mol)
(0.816 atm)(1.14 L) = n(0.08206)(310.15)
Solving for n we get 0.03653 moles.
Now our second part is to figure out the volume AT STP (standard temperature/pressure). In the STP conditions, your temperature defaults to 0 C (273.15 K) and 1 atm. Now there is an easier way to do this, but I'll also show the more comprehensive way. Here is the easier method...
Since 1 mole of every gas occupies 22.4 L at STP, we can simply multiply this by our number of moles. So (22.4L)(0.3653 mol) to give us 0.818272.
However, a more accurate answer can be given like this...
Plugging n back into the same equation and this time resetting pressure to 1 atm and temperature to 273.15 K and conserving our number of moles we get...
(1 atm)(v) = (0.03653 mol)(0.08206)(273.15 K)
v = (0.03653)(0.08206)(273.15)
v = 0.8188 L = 0.819 L or 819 mL
HELPP
explain the difference between molecular and empirical formulas. Which types of compounds are described by the terms formula mass and molecular mass. Use an example to show the steps in calculating the formula mass for K2CO3
Answer:
In the previous section, we discussed the relationship between the bulk mass of a substance and the number of atoms or molecules it contains (moles). Given the chemical formula of the substance, we were able to determine the amount of the substance (moles) from its mass, and vice versa. But what if the chemical formula of a substance is unknown? In this section, we will explore how to apply these very same principles in order to derive the chemical formulas of unknown substances from experimental mass measurements.
Explanation:
tally. The results of these measurements permit the calculation of the compound’s percent composition, defined as the percentage by mass of each element in the compound. For example, consider a gaseous compound composed solely of carbon and hydrogen. The percent composition of this compound could be represented as follows:
\displaystyle \%\text{H}=\frac{\text{mass H}}{\text{mass compound}}\times 100\%%H=
mass compound
mass H
×100%
\displaystyle \%\text{C}=\frac{\text{mass C}}{\text{mass compound}}\times 100\%%C=
mass compound
mass C
×100%
If analysis of a 10.0-g sample of this gas showed it to contain 2.5 g H and 7.5 g C, the percent composition would be calculated to be 25% H and 75% C:
\displaystyle \%\text{H}=\frac{2.5\text{g H}}{10.0\text{g compound}}\times 100\%=25\%%H=
10.0g compound
2.5g H
×100%=25%
\displaystyle \%\text{C}=\frac{7.5\text{g C}}{10.0\text{g compound}}\times 100\%=75\%%C=
10.0g compound
7.5g C
×100%=75%
What is the wavelength of a photon that will be emitted when an electron in the hydrogen atom moves from n
Answer:
Use the Rydberg Equation 1/λ = R(1/n²(final) - 1/n²(initial) where R = 109,678 cm⁻¹. Substitute initial orbital number and final orbital number and solve for wavelength (λ).
Explanation:
Example:
Assume an electron transition from n = 5 to n = 2.
1/λ = 109,678cm⁻¹(1/2² - 1/5²) = 109,678(0.25 - 0.04)cm⁻¹ = 23,032cm⁻¹
λ = 1/23,032cm⁻¹ = 4.34 x 10⁻⁵cm x 10⁻²m/cm x 10⁹nm/m = 434nm
Which diagram best illustrates the difference between distance and
displacement?
Answer:
It is the one that has start and finish and a compass on it...I am sorry I can share images for some reason. And underneath the compass, it says 1.0 Mile. It also has a compass in the bottom right-hand corner.
Explanation:
I just took the quiz and got it correct!
All participants in the Genius dog challenge are border collies which some experts think are the what breed of dog?
As far as the intelligence of canines, it is widely accepted as a fact that the Border Collie is the most intelligent breed of dog.
The conclusion that border collies are the most intelligent breed of dog is credited to a canine psychologist by the name of Stanley Coren. He studied over 138 recognized breeds of dogs to measure the ease with which they learned new commands and the obedience rate of each breed.
Coren studies the learning and obedience of Border Collies over the course of 199 trials and found that this breed of dog performed 95% better than most other breeds, with only 9 of the 138 breeds studied coming close to the results of the border collie. Easily earning the title of the most intelligent breed of dogs.
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Which of the following represents alpha decay?
O A. 169 Gd 108TB +_9e
B. 159 Eu + je → 189 Sm
150
-
C. 90T = 9T +
→ 43
O D. GO → 1945m + He
148
There are two modes in which unstable nuclei of radioactive elements may decay. They are by α - emission or by β - emission. Among the given options, the α - emission is ₆₄¹⁴⁸Gd → ₆₂¹⁴⁴Sm + ₂⁴He. The correct option is D.
What is α - decay?According to the theory of radioactive disintegration, the atoms of all the radioactive elements undergo spontaneous disintegration with the emission of α or β particles to yield atoms of new elements. When a radionuclide decays by emitting an α - particle, it is called α - decay.
When a radionuclide undergoes α - emission, i.e. a helium nucleus there occurs a decrease of 2 units in the atomic number and a decrease of 4 units in the mass number. The new nuclide produced has an atomic number 2 units less and a mass number 4 units less than the parent.
₆₄¹⁴⁸Gd → ₆₂¹⁴⁴Sm + ₂⁴He represents α - emission.
Thus the correct option is D.
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what is another extraction that uses gravity filtration and describe it
Answer -ˋˏ ༻༺ ˎˊ-
A common use for gravity filtration is for separating anhydrous magnesium sulfate (MgSO4) from an organic solution that it has dried (Figure 1.68b). Anhydrous magnesium sulfate is powdery, and with swirling in an organic solvent creates a fine dispersal of particles like a snow globe.
For the formula shown, how many sulfur atoms are represented?
Answer:
Your answer would be 6
Answer:
1 it is 1
Explanation:
give some practical examples where prefixes are used
HELPP PLEASE
this is a weird place to ask but does anyone know a good physical science experimental project that the scientific method can be used on? with homemade materials that doesn’t take more than 2 days to do?
Experiment: Does it Dissolve?
Materials Needed:
4 clear, glass jars filled with plain tap waterFlourSalt Talcum or baby powderGranulated sugarStirrerStep 1: Form a question before starting the experiment.
Step 2: Make a hypothesis for each substance.
Step 3: Scoop a teaspoon of each substance in the jars, only adding one substance per jar. Stir it up!
Step 4: Observe whether or not each substance dissolves and record the findings.
A moon orbits in a roughly circular path around a planet with a mass of 8.6 x 1023 kg. The distance from the center of the moon to the center of the planet is 7.04 x 106 meters. Calculate the speed of the moon in m/s.
Explanation:
A moon orbits in a roughly circular path around a planet with a mass of 8.6 x 1023 kg. The distance from the center of the moon to the center of the planet is 7.04 x 106 meters. Calculate the speed of the moon in m/s.