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Luba_88 [7]
3 years ago
15

an atom has 2 electrons in the first energy level, 8 electrons in the second energy level, and 1 electron in the third energy le

vel. What is the number of core electrons
Chemistry
1 answer:
yKpoI14uk [10]3 years ago
7 0

Answer:2

Explanation:

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Which term best describes the process by which particles escape from the surface of a nonboiling liquid and enter the gas state?
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Evaporating? But that’s with a boiling liquid
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3 years ago
Chemical reaction to make a foam?​
Dmitry [639]

Hydrogen peroxide breaks down into oxygen and water. As a small amount of hydrogen peroxide generates a large volume of oxygen, the oxygen quickly pushes out of the container. The soapy water traps the oxygen, creating bubbles, and turns into foam.
8 0
2 years ago
How many liters are in a .00813M solution that contains 1.55 g of KBr?
Sloan [31]

Answer:

                      1.602 L (or) 1602 mL

Explanation:

             Molarity is the amount of solute dissolved per unit volume of solution. It is expressed as,

                         Molarity  =  Moles / Volume of Solution    ----- (1)

Rearranging above equation for volume,

                         Volume of solution  =  Moles / Molarity    -------(2)

Data Given;

                  Molarity  =  0.00813 mol.L⁻¹

                  Mass  =  1.55 g

First calculate Moles for given mass as,

                   Moles  =  Mass / M.mass

                   Moles  =  1.55 g / 119.002 g.mol⁻¹

                   Moles  =  0.0130 mol

Now, putting value of Moles and Molarity in eq. 2,

                         Volume of solution  =  0.0130 mol / 0.00813 mol.L⁻¹

                         Volume of solution  = 1.60 L

or,

                         Volume of solution  =  1602 mL

5 0
3 years ago
How many grams of hydrochloric acid will react completely with a block of gold is 3.2 cm by 3.8 cm by 2.8 cm, if the density of
JulijaS [17]
Answer:
mass of HCl = 243.5426 grams

Explanation:
1- we will get the mass of the reacting gold:
volume of gold = length * width * height
volume of gold = 3.2 * 3.8 * 2.8 = 34.048 cm^3 = 34.048 ml<span>
density = mass / volume
Therefore:
mass = density * volume
mass of gold = </span>19.3 * 34.048 = 657.1264 grams

2- we will get the number of moles of the reacting gold:
number of moles = mass / molar mass
number of moles = 657.1264 / 196.96657 
number of moles = 3.3362 moles

3- we will get the number of moles of the HCl:
First, we will balanced the given equation. The balanced equation will be as follows:
Au + 2HCl ......> AuCl2 + H2
This means that one mole of Au reacts with 2 moles of HCl.
Therefore 3.3362 moles will react with 2*3.3362 = 6.6724 moles of HCL

4- we will get the mass of the HCl:
From the periodic table:
molar mass of H = 1 gram
molar mass of Cl = 35.5 grams
Therefore:
molar mass of HCl = 1 + 35.5 = 36.5 grams/mole
number of moles = mass / molar mass
Therefore:
mass = number of moles * molar mass
mass of HCl = 6.6724 * 36.5
mass of HCl = 243.5426 grams

Hope this helps :)
4 0
2 years ago
Explain the composition of dna nucleotides and the structure of the dna molecule need help
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A nucleotide is composed of a phosphate group, sugar, and nitrogen base. DNA is made of 2 strands of nucleotides linked together by covalent bonds between the phosphate and sugar of each nucleotide. The strands of nucleotides are linked together by hydrogen bonds creating DNA. Hope this helps and sorry if I made a mistake.

4 0
3 years ago
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