Answer:
1.51e23 atoms
Explanation:
First, using the molar mass of Si (28.1 g/mol), determine the # of moles of Si we have. Then use Avogadro's number (6.022e23 atoms = 1 mol) to convert the # of moles to the # of Si atoms.
(7.02 g Si)([tex]\frac{1 mol}{28.1 g}[/tex]) = 0.250 mol Si
(0.250 mol Si)([tex]\frac{6.022*10^{23} atoms }{1 mol}[/tex]) = 1.51e23 atoms
The atomic mass of Silicon (Si) is 28.09 g/mol. The no. of atoms present in 7.02 g of Si is 1.46 × 10²³.
What is a mole?Any substance containing 6.022 × 10²³ atoms is called one mole of that substance. The no.of moles can be calculated by dividing the given weight by the atomic mass of the substance.
Atomic mass of Si = 28.09 g/mol
Given mass = 7.02 g.
No.of moles = 7.02 g/ 28.09 g/mol
= 0.24 moles
One mole contains 6.02 × 10²³ atoms. Thus 0.24 mole of Si contains 6.02 × 10²³ × 0.24 = 1.46 × 10²³ atoms.
Hence, no.of atoms present in 7.02 g of Si is 1.46 × 10²³ .
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True or false: For a spontaneous redox reaction, the products are stronger oxidizing and reducing agents than the reactants.
Answer: False
Explanation: The stronger oxidizing agent, and stronger reducing agent are the reactants.
The given statement is false , for a spontaneous redox reaction, the reactants are stronger oxidizing and reducing agents than the products.
What are redox reactions?Redox reactions comprise of two parts a reduced part and an oxidized part, which occur simultaneously . The part which is reduced gain electrons and hence there is a increase in oxidation state of the species.
While, the part which is oxidized looses electrons and hence there is a decrease in oxidation state of the species.During redox reactions, there is no net change in the number of electrons . Electrons which are given off in oxidation are used up in reduction.
The ion or molecule which accepts electrons is called as oxidizing agent while the ion or molecule which donates electrons is called as a reducing agent.
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When a gas is collected over water, the partial pressure of water must be subtracted from the total pressure. If the total pressure was 761 mmHg and the pressure for water is 17.2 torr, what is the pressure due to the gas collected
Answer is: the partial pressure of the hydrogen 500 mmHg.
p(total) = 523.8 mmHg.
p(water) = 23.8 mmHg.
p(total) = m(water) + p(hydrogen).
p(hydrogen) = p(total) - p(water)..
p(hydrogen) = 523.8 mmHg - 23.8 mmHg.
p(hydrogen) = 500 mmHg.
mmHg or millimeter of mercury is a manometric unit of pressure.
An atom of sodium has 11 electrons. Make a sketch of a sodium atom, showing how many electrons it has at each energy level. Infer how reactive sodium atoms are.
SOMEONE HELP ME PLEASE :(. I DONT GET IT :(
Please help. A 208 g sample of sodium-24 decays. How much of this radioactive isotope will remain after 3 half
lifes?
Answer: The information about sequential order of the event occurred in the past can be obtained by using only relative dating method.
Explanation:
Relative dating method doesn’t give information about when it happened. It provides sequential order of the events. It is the art of deciding the overall happening of past occasions (i.e., the age of an item in contrast with another), without fundamentally deciding their outright age (for example evaluated age).
In topography, shake or shallow stores, fossils and lithologies can be utilized to correspond one stratigraphic segment with another.
What are the major reservoirs for sulfur
Answer:
the ocean, the ocean floor basalts, evaporite deposits and reduced marine sediments.
Explanation:
How many particles or molecules of hydrogen are there in one mole of H2O?
6.022 × 10^23 ×2 = 12.044 × 10^ 23 atoms
Answer:
In one mole of water, there will exist approximately 6.02⋅1023 water molecules. So, there will be a total of 6.02⋅1023⋅2≈1.2⋅1024 hydrogen atoms.
How do erosions affect land forms?
Erosion is the only cause of land form changes.
Land forms can be created by erosion.
Erosion can prevent land forms from being built.
Land forms can only be created through erosions.
Answer:
the anwser is landforms can be created by erosion
Explanation:
Determina la molaridad de una solución de H2S, si se colocaron 37 ml del ácido en 890 ml de solución. La densidad del H2S es de 1.36 g/ml
Por definición de molaridad y densidad, la molaridad de la solución es 1.66 [tex]\frac{moles}{litros}[/tex].
La concentración molar o molaridad es una medida de la concentración de un soluto en una disolución que indica el número de moles de soluto que están disueltos en un determinado volumen.
La molaridad de una solución se calcula dividiendo los moles del soluto por el volumen de la solución:
[tex]Molaridad=\frac{numero de moles de soluto}{volumen}[/tex]
La Molaridad se expresa en las unidades [tex]\frac{moles}{litros}[/tex].
Por otro lado, la densidad es una magnitud que permite medir la cantidad de masa que hay en determinado volumen de una sustancia.
Entonces, la expresión para el cálculo de la densidad es el cociente entre la masa de un cuerpo y el volumen que ocupa:
[tex]densidad=\frac{masa}{volumen}[/tex]
En este caso, siendo H₂S el soluto, se colocaron 37 ml del ácido, siendo su densidad 1.36 [tex]\frac{g}{mL}[/tex]. Reemplazando en la definición de densidad se obtiene:
[tex]1.36\frac{g}{mL}=\frac{masa}{37 mL}[/tex]
masa= 1.36 [tex]\frac{g}{mL}[/tex]× 37 mL
masa= 50.32 g
Siendo 34 g/mol la masa molar de H₂S, es decir la cantidad de masa que una sustancia contiene en un mol, la cantidad de moles de H₂S puede ser calculada como:
[tex]numero de moles de H_{2}S= 50.32 grams\frac{1 mole}{34 grams}[/tex]
número de moles de H₂S= 1.48 moles
Siendo 890 mL=0.890 L el volumen de la solución, entonces la molaridad puede ser calculada como:
[tex]Molaridad=\frac{1.48 moles}{0.890 L}[/tex]
Molaridad= 1.66 [tex]\frac{moles}{litros}[/tex]
Finalmente, la molaridad de la solución es 1.66 [tex]\frac{moles}{litros}[/tex].
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https://brainly.com/question/17647411?referrer=searchResultshttps://brainly.com/question/21276846?referrer=searchResultsWhat is the frequency of light with a wavelength of 450 nm?
Answer:
The frequency of blue light that has a wavelength of 450 nm is 6.7×1014 6.7 × 10 14 Hz.
Explanation:
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What will be the product or products if zinc (Zn) reacts with hydrochloric acid (HCl)?.
The products of the reaction are Zinc chloride (ZnCl₂) and Hydrogen gas (H₂)
From the question,
We are to determine the product or products when zinc (Zn) reacts with hydrochloric acid (HCl)
To determine the product or products, we will write the chemical equation for the reaction.
The balanced chemical equation for the reaction is
Zn + 2HCl → ZnCl₂ + H₂
Hence, the products of the reaction are Zinc chloride (ZnCl₂) and Hydrogen gas (H₂)
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Rank the following molecules (1st, 2nd, 3rd, 4th) in the order that they melt.
Sucrose
Iodine
Sodium
Paraffin
There is a picture attached
Sodium chloride has the highest melting point while iodine has the least melting point.
The melting points of solid substances depends on the nature of intermolecular forces that exists in the substance. The stronger the magnitude of intermolecular forces in a substance, the higher its melting point.
The order of melting points of the solids shown in question is as follows;
1st - Sodium chloride2nd - sucrose3rd - paraffin4th - IodineSodium chloride has the highest melting points because it is an ionic substance. Among the molecular sucrose and paraffin, sucrose has a higher melting point than sucrose because it has a greater molar mass. Iodine, a molecular substance has the least molar mass and the least melting point in the list.
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Which sample is a pure substance?zinc oxidesugar dissolved in waterpond watersoil.
Answer:
Oxide sugar dissolved in water pond
because water + sugar= sugar melts but the oxide purifys the water.
Explanation:
#carryonlearning!
A fusion reaction always creates which of the following?
a A massive amount of energy.
b A massive amount of heat.
C A more massive atomic nucleus.
d A massive number of smaller nuclei.
A fusion reaction can be regarded as the type of reaction that occurs where two lighter elements come together in a type of reaction giving rise to a heavier/more massive element.
A fusion reaction always creates a more massive atomic nucleus (option c).
When the two lighter nuclei comes together in a reaction, a more heavier/massive nucleus is formed but its mass will still be less than the combined mass of the two reactant nuclei.
This also indicates that the left over mass may have been released as energy.
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A 2.37 g sample of a substance suspected of being pure gold is warmed to 71.8 ∘C and submerged into 15.9 g of water initially at 24.3 ∘C. The final temperature of the mixture is 27.0 ∘C.
Answer:
specific heat capacity of the unknown is 629.66 J/kg C
Explanation:
As we know that gold is heated to 72.3 degree C and mixed with water at 24.8 degree C
Now the final temperature of the mixture is 26 degree C
here we can say that heat given by the gold = heat absorbed by the water
So we will have
Q_{in} = Q_{out}Q
in
=Q
out
2.62 s (72.3 - 24.8) = 15.6 (4186) (26 - 24.8)2.62s(72.3−24.8)=15.6(4186)(26−24.8)
so we will have
s = 629.66 J/kg Cs=629.66J/kgC
so specific heat capacity of the unknown is 629.66 J/kg C
what type of intermolecular force causes the dissolution of nacl in water?
Answer:
ion-dipole forces
Explanation:
positive sodium ion will be attracted to the slightly negative oxygen atoms in the water molecule, while the negative chloride ion is attracted to the slightly positive hydrogen atoms.
Most elements are ____________. The _____________ elements on the left of the stair-step line on the ______________ of Elements are metals or metal-like _____________. Some of the physical properties of metals are ______________ (shininess) and ___________ density. They are also good conductors of ___________ and ______________. Metals can be hammered into __________sheets.
Answer:
metals, 88 , periodic table , luster , heat, electricity , thin, right, opposite , appearance , luster , malleable , ductile, opposite , shiny, moderately
Explanation:
metals, 88 , periodic table , luster , heat, electricity , thin, right, opposite , appearance , luster , malleable , ductile, opposite , shiny, moderately Is the answer.
(Hope this helps can I pls have brainlist (crown)☺️)
whats the formula for lithium nitride
Answer:
Lithium nitride. Trilithium nitride. 26134-62-3. Lithium nitride (Li3N) Li3N.
How many moles of methane are produced when 25. 1 moles of carbon dioxide gas react with excess hydrogen gas.
Answer:
25.1 moles
Hence it can be seen that when 25.1 moles of carbon dioxide gas react with excess hydrogen gas, 25.1 moles of methane gas are produced.
A copper sulphate solution contained 0.100 moles of copper sulphate dissolved in 0.500 dm cubed of water. Calculate the mass of copper sulphate in 30.0cm cubed of this solution. Relative formula mass (mr): CuSO4= 159.5
Answer:
cm^3 —> dm^3
divide by 1000
159.5 — Mr of CuSO4
n (moles in mol) = c (concentration in mol/dm^3) * v (volume in dm^3)
0.100 mol of CuSO4 dissolved in 0.5dm^3 of water
calculate for mass of CuSO4 dissolved in 0.03dm^3 (30cm^3) of the solution
n = m/Mr
m = n*Mr
if 0.1 mol is dissolved in 0.5 dm^3 of water
0.5/0.03 ≈ 16.66666667
0.1 = 0.05
0.1 / 16.66666667 = 0.006
0.5 / 16.66666667 = 0.03
0.006 (mol of CuSO4) = 0.03 (dm^3 solution)
0.006 * 159.5 = 0.957 g
I think this is the answer
The mass copper sulphate CuSO₄ in 30ml solution is 957.6g.
How to determine the mass of copper sulphate in the given solution?To determine the mass of copper sulphate in the given solution, compare both the molarity given
M₁V₁=M₂V₂
n₁/V1=n₂/V2
0.1/0.5=n₂/30 cm³=ml
n₂=6 moles
6×159.5=957.6g
Multiply the calculated moles with the relative mass/molecular mass to get the mass of CuSO₄.
hence, the mass of CuSO₄ is 957.6g
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A bar of copper (Copper = 0.385 J/g.°C) and a bar of aluminum (Aluminum = 0.897 J/g.°C) have the same mass. Which requires more energy to increase the temperature from 20°C to 30 °C?
Answer:
Aluminum
Explanation:
Define ionic bond and explain the formation of nacl and mgo
a.
Ionic bond is a bond in which there is complete transfer of valence electrons between atoms.
The atom that loses the valence electron is called the electron donor while the atom that accepts the electron is called the electron acceptor.
Ionic bond usually occurs between metals and non metals.
Ionic bond is a bond in which there is complete transfer of valence electrons between atoms.
b.
The force of attraction between Na⁺ and Cl⁻ forms the ionic bond.
In the formation of NaCl, Na has one valence electron in its outermost shell and Cl needs one electron to complete the stable octet configuration. Na donates its valence electron to Cl to form the ionic bond. So, the Na atom becomes positively charged with a charge of +1 while the Cl atom becomes negatively charged with a charge of -1.Since the atoms are now charged, the force of attraction between them forms the ionic bond.
c.
The force of attraction between Mg²⁺ and O²⁻ forms the ionic bond.
In the formation of MgO, Mg has two valence electrons in its outermost shell and O needs two electrons to complete the stable octet configuration. Mg donates its two valence electron to O to form the ionic bond. So, the Mg atom becomes positively charged with a charge of +2 while the O atom becomes negatively charged with a charge of -2.Since the atoms are now charged, the force of attraction between them forms the ionic bond.
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An ionic or electrovalant bond is a type of chemical bond, which is formed from two ions (charged atoms by loosing or gaining electrons) having opposite charges.
Ionic bonds are formed from the transfer of electrons from one atom to another. As the electrons are transferred there occurs a positively charged ions (cations) and a negatively charged ions (anions). These ions are held together in a crystal lattice structure by the strong electrostatic attraction between the positively charged cations and negatively charged anions.
The electrons are transferred as the atoms have tendencies to achieve a stable electronic configuration. They do this to attain a stable atomic structure. By transferring the electrons they attain their octet or duplet.
Sodium chloride(NaCl) is formed when the atom of sodium combines chemically with chlorine atom to generate an ionic compound.
Since sodium has an atomic number of 11, its electronic configuration is 2, 8, 1. There is only one electron in the outermost shell of a sodium atom. Therefore, the sodium atom gives one electron to produce the sodium ion Na⁺.
Chlorine has an atomic number of 17. Hence, its electronic configuration is 2, 8, and 7. The chlorine atom contains seven electrons in its outermost shell and requires one more electron to create the inert gas’s stable, eight-electron configuration. Consequently, a chlorine atom accepts one electron and creates the negatively charged chloride ion (Cl⁻).
When sodium interacts with chlorine, it donates its outermost electron to the chlorine atom, forming a sodium ion (Na⁺) and a chloride ion (Cl⁻) by accepting an electron. The strong electrostatic force of attraction between the newly created ions, holds sodium and chloride ions together to create sodium chloride, Na⁺Cl⁻ or NaCl.
Similarly in the case of Magnesium Oxide (MgO) is formed from the chemical interactions of Magnesium and oxygen atoms, leading to the formation of an ionic compound.
Since magnesium has an atomic number of 12, its electrical configuration is 2, 8 and 2, there is just 2 electrons in the outermost shell of a Magnesium atom. Therefore, the magnesium atom gives two electron to produce the Magnesium ion Mg²+ .
Oxygen has an atomic number of 8. Hence, its electronic configuration is 2 and 6, the oxygen atom contains 6 electrons in its outermost shell and requires 2 more electron to create the inert gas’s stable, eight-electron configuration. Consequently, a oxygen atom accepts 2 electronelectrons and creates the negatively charged oxide ion (O²-).
When magnesium interacts with oxygen, it donates its outermost electrons to the oxygen atom, generating a Magnesium ion Mg²+ . And an oxygen ion (O²⁻) by acquiring 2 electrons. The attractive electrical force holds magnesium and oxygen ions together to create sodium chloride, Mg²⁺ O²⁻ or MgO.
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Which of the following best describes the cell below
plant cell
Protist cell
Eukaryotic cell
Prokaryotic cell
Answer:
Prokaryotic cell
Explanation:
If you search it up you will see that the prokaryotic cell looks exactly alike with the picture you have posted.
How does a phase change from solid to liquid occur in a substance?
A. Heat energy is released from the substance, weakening the electrical attraction between molecules.
B. Heat energy is released from the substance, strengthening the electrical attraction between molecules.
C. Heat energy is added to the substance, weakening the electrical attraction between molecules.
D. Heat energy is added to the substance, strengthening the electrical attraction between molecules.
Answer:
see below
Explanation:
1. Heat energy is added to the substance, weakening the electrical attraction between molecules.
2. Both the melting point and boiling point are lower.
3. dipole
4. Water and ethanol have different molecular structures.
5. The lone pairs of electrons in the oxygen atom causes the molecule to be bent; the oxygen atom has a partial negative charge, while the hydrogen atoms have partial positive charges.
[quizlet: captncrun]
Heat is a form factor that changes the solid from light to light to gaseous mediums. The phases take place in a cyclic manner.
The solid to liquid changes take place due to the melting or fusion, solid to gas take lace through the sublimation, liquid to gas is by vaporization, and gas to liquid is condensation. Thus the heat is added and leads to the weakening of the electrical attraction within the molecules.Hence the correct option is C.
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brainly.com/question/25664350.
when calculating specific heat what if the change in temperature is negative?
Answer:
If AT and q are negative, then heat flows from an object into its surroundings. If a substance gains thermal energy, its temperature increases, its final temperature is higher than its initial temperature, then AT>0 and q is positive.
Please help I have a C in advance chemistry
Answer:
I think it's 2.50M IM NOT SURE THOUGH SO I RECOMMEND WAITING FOR ANOTHER ANSWER
how well did the landmases fit together this time
Answer:
The theory of continental drift is most associated with the scientist Alfred Wegener. In the early 20th century, Wegener published a paper explaining his theory that the continental landmasses were “drifting” across the Earth, sometimes plowing through oceans and into each other. He called this movement continental drift.
Explanation:
Which ingredients are needed to transform nadp to nadph?.
Answer:
according to online:
"Hydrogen ions are transported with the electrons along the chain of reactions. In photosystem I, the electrons are energized, and the energy is stored in molecules of NADP+. During these reactions, the NADP+ molecules are reduced by the addition of electrons. A hydrogen ion is added to NADP+ to form NADPH."
Explanation:
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Choose the statement that is TRUE. Question 26 options: Outer electrons efficiently shield one another from nuclear charge. All of the answers are true Valence electrons are most difficult of all electrons to remove. Core electrons effectively shield outer electrons from nuclear charge. Core electrons are the easiest of all electrons to remove.
The statement which is true is Core electrons effectively shield outer
electrons from nuclear charge.
Core electrons are those which are in close proximity with the nucleus. The
core electrons repel the outer electrons farther away from the nucleus to
shield it from nuclear charge.
The valence electrons are usually found in the outermost part of the shell
and they are the easiest to remove due to the fact that they have to achieve
a stable octet configuration which makes them easily removed during
chemical reactions.
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Answer: core electrons effectively shield outer electrons from nuclear charge
Explanation:
what is the coefficient for 4K2CO3
An iron object alloyed with cobalt rusts more quickly than a pure iron object. However, an iron object alloyed with manganese rusts less quickly than a pure iron object under the same conditions. This is true because: __________
a. cobalt is a stronger reducing agent than iron
b. iron is a stronger reducing agent than manganese
c. cobalt exhibits more metallic character than either iron or manganese in the iron-manganese alloy
Rusting is an electrochemical reaction. Iron rusts faster when alloyed with cobalt than when alloyed with manganese because, in the iron-manganese alloy, manganese is rendered the anode and iron is rendered the cathode
An alloy is a combination of two metals. There are various reasons for producing alloys such as greater tensile strength, corrosion resistance and improved aesthetic appearance.
When iron is alloyed with cobalt, the iron rusts faster than pure iron because iron is rendered the anode and cobalt is rendered the cathode. When the iron is alloyed with manganese, it rusts more slowly than pure iron because in the iron-manganese alloy, manganese is rendered the anode and iron is rendered the cathode.
Missing parts;
An iron object alloyed with cobalt rusts more quickly than a pure iron object. However, an iron object alloyed with manganese rusts less quickly than a pure iron object under the same conditions. This is true because
(1) cobalt is a stronger reducing agent than iron
(2) iron is a stronger reducing agent than manganese
(3) cobalt exhibits more metallic character than either iron or manganese
(4) in the iron-manganese alloy, manganese is rendered the anode and iron is rendered the cathode
(5) in the iron-cobalt alloy, cobalt is rendered the anode and iron is rendered the cathode
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