Answer:a)No of moles of Aluminium=0.4703
b)number of aluminum atoms=2.832 x 10^23 atoms
Explanation:
a)Given that The Amount/ Mass of Aluminum is 12.69g
We know that
No of moles =Mass/ Molar mass
Molar mass of Aluminium, Al is 26.982 g/mol
No of moles =12.69g/26.982 g/mol
No of moles =0.4703
Also
b) 1 mole of aluminium must contain 6.022 x 10^23 atoms of aluminium
which is known as Avogadro's constant.
Therefore, 0.4703 moles will contain 0.4703 x 6.022 x 10^23 atoms =2.832 x 10^23 atoms
An electric kettle draws a current of 6.50 A while it is plugged into a 120-V
electrical outlet. What power does the kettle use?
Answer:
780 watts
Explanation:
formula to find power when given amps and voltage
P = A x V
=6.50a x 120V
= 780 W (watts)
1. The electronic configuration of chlorine is
1. 2,7
II. 2,8,8,7
III. 2,8,7
IV. 2,7,8
Answer:
Chlorine has atomic number 17. Its electronic configuration is 2, 8, 7. It is the second-lightest of the halogens, it appears between fluorine and bromine in the periodic table.
Answer:
III
Explanation:
From the periodic table, Chlorine(Cl) has 17 protons.
And when arranging the proton of elements each shell has a number protons it can take, i.e
2,8,8,8..........
The first shell can only take a maximum of 2 protons while the second shell upwards takes a maximum of 8 protons
Now we want to arrange Chlorine;
1st shell = 2
2nd shell = 8
2 + 8 = 10
17(no. of Chlorine protons) - 10
= 7
therefore,
3rd shell = 7
Therefore,
The electronic configuration of chlorine is
2,8,7
What type of structure are ionic lattices?
Big structures
Small structures
Tiny structures
Giant structures
Answer:
Giant structures
Explanation:
An ionic compound is a giant structure of ions. The ions have a regular, repeating arrangement called an ionic lattice . The lattice is formed because the ions attract each other and form a regular pattern with oppositely charged ions next to each other.
Which kind of energy is stored in the chemical bonds of molecules found in
wood?
A. Mechanical energy
B. Potential energy
C. Gravitational energy
D. Kinetic energy
Answer:
B. Potential energy
Explanation:
It's not mechanical energy, because it is not doing work
It's not kinetic energy because it;s not moving
It's not gravitational energy because it is not above the ground
It is potential energy because it is stored energy
If the half life of iridium-182 is 15 years, how much of a 3 gram sample is left after 2 half-lives?
A) .57 grams
B) .70 grams
C) 2.25 grams
D) .75 grams
Answer:
D. 0.75 grams
Explanation:
The data given on the iridium 182 are;
The half life of the iridium 182, [tex]t_{(1/2)}[/tex] = 15 years
The mass of the sample of iridium, N₀ = 3 grams
The amount left, N(t) after two half lives is given as follows;
[tex]N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}} }[/tex]
For two half lives, t = 2 × [tex]t_{(1/2)}[/tex]
∴ t = 2 × 15 = 30
[tex]\dfrac{t}{t_{(1/2)}} = \dfrac{30}{15} = 2[/tex]
[tex]\therefore N(t) = 3 \times\left (\dfrac{1}{2} \right )^2 = 0.75[/tex]
∴ The amount left, N(t) = 0.75 grams
The diagram shows the basis for forming which of the following?
O nucleic acids
O proteins
O polysaccharides
O lipids
Which of these is an example of a prosthesis?
A. A hearing aid
B. A textbook
C. Gloves
D. A pair of boots
Answer:
hearing aid
Explanation:
an artificial body part
A hearing aid is an example of a prosthesis. Therefore, option A is correct.
A prosthesis is an artificial device or replacement for a missing body part or function. In the case of a hearing aid, it is a device designed to assist people with hearing loss by amplifying sound. It acts as a substitute for the natural function of the ear.
A textbook is a written educational resource, gloves are protective coverings for the hands, and a pair of boots is footwear. These items do not serve as artificial replacements for missing body parts or functions.
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Which of the following reactions would be the fastest?
A large lump of zinc with high concentration of sulfuric acid.
Small strips of zinc with high concentration of sulfuric acid.
Powdered zinc with low concentration of sulfuric acid.
Powdered zinc with high concentration of sulfuric acid.
2 DONT KNOW
Answer:
it should be powdered zinc with high concentration of sulfuric acid
what are examples of soluble salts (metal+acids)
Answer:
Chloride salts - made of HCI
Nitrate salts - made of HNO3
Sulfate salts - made of H2SO4
These are all the examples I could think of.
125 cm3 of a solution contains 0.25 moles of the solute. What is the concentration of the solution?
Answer:
Explanation:
125 cm3 -> 0.125 L
M = no. mole / volume (L)
M = 0.25 / 0.125 = 2 M
Is soup pure or impure?
Answer:
I think it's impure . Hope this helps you
Answer:
I think is pure but not 100% pure.
303.8 liters volume will be occupied by 217.0 grams of methane gas at STP.
True
False
Answer:
False
Explanation:
It will occupy 271.7
ANSWER FAST
What is the relationship between Ka and Kb with Kw?
(a) The sum of Ka and Kb equals the auto-dissociation constant for water.
(b) The product of Ka and Kb equals the auto-dissociation constant for water.
(c) The quotient of Ka and Kb equals the auto-dissociation constant for water.
(d)The difference of Ka and Kb equals the auto-dissociation constant for water.
Which statement best describes the diagram
Explanation:
the answer will be A
The catalyst cannot be at point A since that's the reactant
Pathway B requires more energy, which makes it slower and harder for the reaction to finish
point D is the product
2.7 x 10^25 molecules of MnO equals how many moles?
Answer:
27 and 24 zeroes following it
Explanation:
10^25 is 100...(continues for 25 zeroes)
Now we multiply it by 2.7, making it 24 zeroes afterwards.
Avogadro's numbers are used to calculate the number of moles from molecules. There are 44.8 moles in MnO.
What are molecules?Molecules are the unit of the compound that may have the same or different atoms in it. The number of molecules is used to calculate moles from Avogadro's number.
By Avogadros number 1 mole of substance = 6.02 x 10²³ molecules
So, 2.7 x 10²⁵ molecules will have moles:
(2.7 x 10²⁵ molecules × 1 mole) ÷ (6.02 x 10²³ molecules) = 0.448 × 10² moles
Therefore, there are 44.8 moles of MnO.
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What is this picture an example of?
A. carbon cycle
B. nitrogen cycle
C. water cycle
D. ecological succession
PLEASE HELP
Sorry if the picture is bad Quality
Answer:
i think it is D
Explanation:
i dont know what you are learning but ecological succession is the change of enviroment pretty much.
How many atoms of oxygen are represented in 2Al 2 (CO 3 ) 3 ?
A. 3
B. 6
C. 9
D. 18
In a nonpolar covalent bond, electrons are
a. Located in a mobile "sea" shared by many ions
b. Transferred from one atom to another
c. Shared equally between two atoms
d. Shared UNequally between two atoms
Answer: c. Shared equally between two atoms
Electrons are shared equally because the atoms have the same electronegativity.
When the pH of a solution is changed from 4 to 3, the hydronium ion concentration of the
solution
A)
increases by a factor of 10
B)
decreases by a factor of 100
C)
increases by a factor of 100
D)
decreases by a factor of 10
Answer:increases by a factor of 10
Explanation: the concentration of the solution changed from 4 to 3
Calcule el peso de cromato sodico, Na2CrO4, necesario para preparar 200g de una disolución al 20% de Na2CrO4
Answer:
40g de cromato sódico serán necesarios
Explanation:
Una solución 20% de Na2CrO4 contiene 20g de Na2CrO4 por cada 100g de solución (Esto es, soluto + solvente). Para preparar 200g de la disolución en mención serán necesarios:
200g solucion * (20g Na2CrO4 / 100g Solución) =
40g de cromato sódico serán necesariosmedian of 4, 6 ,9 helppp
For the data set 1, 1, 2, 5, 6, 6, 9 the median is 5. For the data set 1, 1, 2, 6, 6, 9 the median is 4.
hope it helps you
Answer:
The median is 6, since it is the mid value of the set
What is S for silicon tetrachloride, SiCl4
S denotes the ''number of shared electron pairs by an atom'', Hence, Silicon shares its 4 electrons with 4 Cl-atoms. Thus the Value of S is 4 in SiCl₄ .It is also known as covalency
What is Covalency ?
The number of covalent bonds that a particular atom can make with other atoms in forming a molecule.
Covalent bond id formed by the sharing of electron between two atoms.
Hence, Silicon shares its 4 electrons with 4 Cl-atoms. Thus the Value of S is 4 in SiCl₄ . It is also known as covalency
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PLEASE HELP!!!!!!
The average number of drops of NaHCO3 in the titration lab was 142. Calculate the number of moles of NaCHO3 that were required to neutralize the CH3COOH in the vinegar.
- 1 mole of acetic acid was required for 2 moles of sodium bicarbonate
- 1 mole of acetic acid was required for 1 mole of sodium bicarbonate
- 2 mole of acetic acid was required for 1 mole of sodium bicarbonate
- 1 mole of acetic acid was required for 3 mole of sodium bicarbonate
Answer: The correct option is 1 mole of acetic acid was required for 2 moles of sodium bicarbonate
Explanation:
We are given:
Average number of drops of sodium bicarbonate = 142
The chemical equation for the reaction of sodium bicarbonate and acetic acid in vinegar follows:
[tex]NaHCO_3+CH_3COOH\rightarrow CH_3COONa+H_2CO_3[/tex]
From the stoichiometry of the reaction:
1 mole of sodium carbonate reacts with 1 mole of acetic acid in vinegar.
Hence, the correct option is 1 mole of acetic acid was required for 2 moles of sodium bicarbonate
A few substances are arranged in the increasing order of ‘forces of attraction’ between their particles. Which one of the following represents a correct arrangement?
(a) Water, air, wind
(b) Air, sugar, oil
(c) c Oxygen, water, sugar
Answer:
A.
Explanation:
PO WATER,AIR,WIND
Explain how to convert a mass of compound A to a mass of compound D in words using the following reaction:
2A + 4B = C + 3D
You don't have to just give me the answer but if you can help me understand id appreciate it greatly
Answer:
1. Convert the mass of A to moles dividing in molar mass
2. Convert the moles of A to moles of D (2mol A = 3mol D)
3. Convert the moles of D to mass multiplying by its molar mass
Explanation:
As you can see in the equation, 2moles of A produce 3 moles of D, the equation is:
2mol A = 3mol D
But in the problem you are having the mass of A and you need the mass of D. That means you require to convert the mass of A to moles. With the moles of A you can find the moles of D and, as last, you need to convert the moles of A to mass.
To convert mass to moles or vice versa you must use Molar Mass. That means, the answer is:
1. Convert the mass of A to moles dividing in molar mass2. Convert the moles of A to moles of D (2mol A = 3mol D)3. Convert the moles of D to mass multiplying by its molar massSketch 10 atoms of aluminum and 6 molecules of oxygen gas in the container on the left. In the right container, sketch the contents after the reaction is complete.
Answer:
Sketch 10 atoms of aluminum and 6 molecules of oxygen gas in the container on the left. In the right container, sketch the contents after the reaction is complete.
Explanation:
The balanced chemical equation of the reaction is:
[tex]4Al + 3 O_2 -> 2Al_2O_3[/tex]
Though there are 10 atoms of Al, only four atoms will react with every three molecules of oxygen.
Hence, right side the product formed is --- Al2O3.
what is the molecular weight of a gas which diffuses 1/50 as fast as hydrogen
How many grams of FeCl3 are needed to make 1.5 L of a solution with a molarity of 0.450 M?
What can a nation do to improve the exchange rate of its currency?
A.
try to improve its balance of trade
B.
try to decrease its trade surplus
C.
try to lower its gross domestic product (GDP)
D.
try to export less while importing more
Answer:
A
Explanation:
balance the trades and improving them
Answer:
A:try to improve it's balance of trade
Explanation:
Suppose I have enough ingredients to make 25 cookies, but when I go to bake them, I only get 5. What percent yield did I obtain?
Answer:
Explanation:
What is the "theoretical yield" of cookies from each of the "reactants?"
Theor. yield from eggs
=
12
eggs
×
24 cookies
1
egg
=
288 cookies
Theor. yield from vanilla
=
24
tsp vanilla
×
24 cookies
1
tsp vanilla
=
576 cookies
Theor. yield from salt
=
82
tsp salt
×
24 cookies
0.5
tsp salt
=
3936 cookies
Theor. yield from baking soda
=
84
tsp baking soda
×
24 cookies
0.5
tsp baking soda
=
4032 cookies
Theor. yield from chocolate chips
=
3
cups chocolate chips
×
24 cookies
1.333
cups chocolate chips
=
54 cookies
Theor. yield from sugar
=
11
cups sugar
×
24 cookies
0.5
cup sugar
=
528 cookies
Theor. yield from brown sugar
=
4
cups brown sugar
×
24 cookies
0.5
cup brown sugar
=
192 cookies
Finally, "we leave it as an exercise for the student" to calculate that
Theor. yield from margarine = 72 cookies
b. Identify the limiting reactant
The limiting reactant is the amount of chocolate chips because they can produce the smallest amount of cookies.
c. Determine the theoretical yield
The theoretical yield is 54 cookies, because that is all you can get from the chocolate chips provided.
The percent yield obtained on baking the cookies is 20 % and the theoretical yield is 25 cookies.
What is percent yield?Percent yield is defined as the ratio of actual yield to the theoretical yield multiplied by 100. If the actual and theoretical yield are same then the percent yield is 100%.If actual yield is less than the theoretical yield then the percent yield is less than 100%.Reason of this condition arising is the incompletion of reaction or loss of sample during recovery process.
In cases where percent yield is over 100% it indicates that more sample is recovered than the predicted amount.This condition arises when there are other simultaneous reactions taking place leading to the formation of product. It can also arise if there is incomplete removal of impurities from the sample .
As cookies obtained is 5 it is observed yield while 25 is theoretical yield so the percent yield, 5/25×100=20%.
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