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]
Plants exchange carbon dioxide, water, and oxygen with their surrounding environment through openings in their ________ called _________.
A.
leaves, xylem
B.
roots, guard cells
C.
leaves, stomata
D.
stems, sori
plzz help me cant remember the parts of the flower.
A is the petal and b is the leaf. I think.
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HOPE IT HELPS:)
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dentify the parts of the atom that are labeled in the diagram.
Answer:
Our current model of the atom can be broken down into three constituents parts – protons, neutron, and electrons. Each of these parts has an associated charge, with protons carrying a positive charge, electrons having a negative charge, and neutrons possessing no net charge.
Read the following statement:
The amount of force acting on an object is equal to its mass times its acceleration.
Does the statement describe a scientific law?
No, because it is applicable to all cases in the natural world
Yes, because it is applicable to just a few cases in the natural world
No, because it describes the relationship between force and acceleration
Yes, because it describes how mass and acceleration affect force
Answer:
D
Explanation:
the acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of an object
some uses of sodium bicarbonate
Answer:
Sodium bicarbonate is an antacid used to relieve heartburn and acid indigestion. Your doctor also may prescribe sodium bicarbonate to make your blood or urine less acidic in certain conditions. This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
An electron is present at an energy level with an energy of 5.44 x 10−19 J. After a second, the electron is present at an energy level with energy, 2.4 x 10−19 J. What most likely happened during the transition?
A photon of energy 7.84 x 10−19 J was released.
A photon of energy 3.04 x 10−19 J was released.
A photon of energy 7.84 x 10−19 J was absorbed.
A photon of energy 3.04 x 10−19 J was absorbed.
Answer:
Explanation:
b
Someone plz help me asap
Answer: it would be the stem and the roots of the plant
Explanation:
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 :)
A city carrier resigns and trains as an office receptionist this is a person’s metabolism is likely to
A reaction mixture initially contains 0.236 mol FeS and 0.670 mol HCl. Once the reaction has reached completion, what amount (in moles) of the excess reactant is left
Answer:
= 0.198 mole H₂S in excess
Explanation:
A quick way to determine limiting reactant is to convert reactant values given to moles and divide by respective coefficient. The smaller value is the limiting reactant other reactants will be in excess. However, when working problem, use mole values given to solve, not results of division.
FeS + 2HCl => FeCl₂ + H₂S
0.236mole/1 0.670mole/2
= 0.236 = 0.335
limiting reactant is FeS; HCl will be in excess.
Problem solution
0.236mole FeS used + 2(0.236 mole HCl used)
=> 0.236 mole FeCl₂ + 0.236 mole H₂S + (0.670 - 0.472) mole HCl in excess or, 0.198 mole H₂S in excess.
Hope this helps. :-)
NEED ANSWER ASAP!! will give brainlist
Which best explains why nanofiltration is an important new technology?
A. It can be used to help regions that have a short supply of usable water.
B. It can be used as an energy source to produce electricity in regions with limited coal.
C. It recycles wastewater to be reused for geothermal energy.
D. It collects solar energy to generate electrical power.
Explanation:
Our Direct Nanofiltration (dNF) membranes offer the unique combination of a low fouling hollow fiber configuration with the ability to remove organics and salinity (hardness) from water in one simple step. Other than a strainer, no further pre-treatment is required. We manufacture our membranes with a patented layer-by-layer process, where multiple nano-scale layers are deposited on a membrane support. This method enables very precise and controlled rejection and flux properties of the membrane. A unique solution for troubled water.
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
Phản ứng phân hủy của 1 este trong môi trường kiềm: RCOOR’ + NaOH → RCOONa + R’OH
Để một nửa lượng ban đầu của RCOOR’ và NaOH chuyển thành sản phẩm ở 270C cần thời gian là 200
phút. Hỏi ở 570C cũng để chuyển một nửa lượng ban đầu của RCOOR’ và NaOH thành sản phẩm thì cần
bao nhiêu phút? Cho biết hệ số nhiệt độ của phản ứng trên = 2,8.
please help me I cant remember the parts of the flower and I really need help.
Hydrocarbons (alkanes, alkenes, alkynes) have all the properties below except one.
Which is not a property of hydrocarbons?
A.nonpolar
B.high melting and boiling points
C.insoluble in water
D.flammable
Answer:
B
Explanation:
The answer is B. All hydrocarbons are nonpolar, they are insoluble in water and they are highly flammable. Now, not all hydrocarbons have high boiling and melting point. For example, methane (CH4) has a boiling point of something clode to -161°C, and that is low. The boiling point increases when the number of carbon atoms in a compound increases, and based on methane and this theory, not all hydrocarbond have a high boiling point. This makes option B be the correct answer.
How many grams are in 0.39 moles of water
Answer: 7.025959200000001
Explanation:
A carrot originally has a mass of 0.39g and after being left in a salt solution overnight it gained 0.3g. Calculate the percentage mass increase of the carrot.
Answer:
77%
Explanation:
The formula for finding percent change is change/original.
So, you have to do 0.3/0.39
You have to divide this to get 0.769 which can be rounded 0.77
0.77 as a percentage is 77%
So, the percentage mass increase of the carrot is 77%
How many atoms...
NAC2H3O2
Answer:
one Sodium (Na) atom, two oxygen (O) atoms, two carbon (C) atoms, and three hydrogens (H) atoms
Explanation:
Help please :) with this
Answer:
option C 5
hope this answer helps you dear! take care
Answer:
5, the coefficient is the number right before the variable. The ² and ³ (even though Mines on top and yours is on the bottom) are not coefficient because. . . well it just doesn't make sense.
Certain __________ metals like gold are found as pure metals rather than ores in the earth. Complete the sentence.
Answer:
nonreactive
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:)
how many grams of C2H5OH would get if you started with 5.0 g
Answer:
92.13688 grams
What happens to the kinetic energy of the bowling ball when it reaches the pins?
Answer:
The bowling ball has kinetic energy as it moves toward the pins.
Explanation:
Answer:
Most of it is transferred to the pins, but some of it is changed into heat and sound energy.
Explanation:
study island
List the metals that form only one type of ion (that is, metals whose charge is invariant from one compound to another). What are the group numbers of these metals
this question is in reference to the formation and naming of ionic compounds. Specifically, they want you to give examples of three ionic compounds with a metal to nonmetal ratio of 2 to 1. That means we need to have two metal atoms to metal ions, which are typically cat ions for every one non metal atom or an ion. In order for this to occur, we need to have the metal with half the charge of the nonmetal or the non metal with double the charge of the metal. So an example might be something like sodium sulfide. Sodium has one valence electron. It can give up sulfur needs to valence electrons in order to achieve an octet. So we need to. Sodium seems to give up one electron each to total so that sulfide can achieve an octet. Another one might be potassium oxide. Similar scenario. We've got potassium giving up one valence electron oxygen requiring too. So we need to potassium to supply the to valence electrons that oxygen needs to achieve an octet and lithium. Also in Group one A and alkali metal wants to give up just one valence electron to achieve an octet well to achieve, I guess a duet to be more like helium, and so it gives up one. If we have two of them, then we can provide the to valence electrons that sulfur needs. So this is sodium sulfide, potassium oxide and lithium sulfide. Remember when we name Ionic compounds? We named the Cat Ion with the name of the element and the anti on with the name of the Element, but with the ending oven of ID, a suffix of ID because each one of the cat ions donated their valence electrons to the anti on so the an ion could achieve an octet. Then all of the's will have an octet of valence electrons. Sulfur had six sodium had one. There were two of them, so we have a total of eight.
The metals that can form only one type of ion are Li, Al, Ca, Ba, Rb, W,Na, Mg and Sr. They are called alkali metals.
Cobalt, Co is stable in both +2 and +3 oxidation state. So it can variable.
Lithium, Li only have +1 charge. So it is invariable from one compound to other.
Lead, Pb is variable as it has +2, +4 charge in which it is stable.
Pd has +2, +4 charge in which it is stable. So, It is variable.
Copper, Cu has +1, +2 charge. It is also variable. Potassium, K has only +1 charge. It is invariable. Aluminum, Al has only +3 charge. It is invariable.
Cesium, Cs is only stable in +1 charge. It is invariable. Molybdenum, Mo is stable in +4 and +6. It is variable. Calcium, Ca and Barium Ba are stable in +2 charge. It is invariable.
Rubidium, Rb is stable in +1 charge. It is invariable. Tungsten, W is stable in +6 charge. It is invariable. Iron, Fe is stable in +2, +3 charge. It is variable. Sodium, Na is stable in +1 charge. It is invariable. Mg and Sr are stable in +2 charge. It is invariable. Vanadium, V has +2, +3, +4, +5 charges. So, It is variable.
To know more about alkali metals
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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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Copper is an example of?
Transition Metal
Noble Gases
Alkali Metal
Halogen
Answer:
Transition Metal
Explanation:
If you look at a periodic table, you can see that Cu is a transition metal.
Predict the product of each monosaccharide oxidation reaction.
The complete oxidation of the monosaccharide shown will create a carboxylic acid.
Monosaccharides can be oxidized to carboxylic acids. Recall that monosaccharides have an aldehyde or ketone group at one end and a CH2OH group at the other end.
For the monosaccharide shown, oxidation may lead to the conversion of COH group to acid (-COOH). This confirms the presence of -COH yielding the product C4H8O5.
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Answer:
1
Explanation:
Answer:
Um.....
Explanation:
Thanks for the pts
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