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9966 [12]
4 years ago
9

Niels Bohr proposed his model of the atom about ________

Chemistry
2 answers:
jok3333 [9.3K]4 years ago
7 0
About 100 years ago. I hope that’s the answer you’re looking for :)
nirvana33 [79]4 years ago
6 0
100 years ago.. i think! Brainiest please ? :D
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How many moles of HCl are present in 0.70 L of a 0.63 M HCl solution?
eimsori [14]
So the molarity equation is moles of solute/liters of solution. so i’m pretty sure the answer should be 0.63/0.70= .9
7 0
3 years ago
One mole of Ca is equal to how many atoms​
Irina18 [472]

Answer:

1 mole of calcium contains 6.023 \times 10^{23} atoms.

Explanation:

1 mole is the amount of a substance that contains exactly 6.023\times 10^{23} constituent particles. 1 mole of a substance is always equal to the atomic mass of the element.

Hence, 1 mole of calcium will also have 6.023\times 10^{23} atoms.

Number of atoms in 1 mole calcium = 6.023 \times 10^{23} atom

4 0
4 years ago
To gain an idea as to how many atoms are in a gram or so of copper, use the larger balance
anygoal [31]

Answer:

Explanation:

To solve this problem, we must understand the relationship between mass of a substance and the number of atoms.

Atoms are the smallest indivisible particles of any matter. A substance can be made up of several number of atoms in their space.

The mass of any substance is a function of the amount of atoms its contains.

The mass of a substance is related in chemistry to the amount of atoms its contains using the parameter called the number of moles.

A mole is the amount of substance that contains the Avogadro's number of particles. This number is 6.02  x 10²³ particles. The particles here can be protons, neutrons, electrons, atoms e.t.c.

Now,

             Number of moles  = \frac{mass}{molar mass}

          Molar mass of copper  = 63.6g/mole

         Number of moles  = \frac{2}{63.6}  = 0.03mole

Since 1 mole of a substance contains  6.02  x 10²³atoms

        0.03 mole of copper will contain 0.03 x  6.02  x 10²³atoms

                                                    = 1.89 x 10²² atoms

He needs to add 1.89 x 10²² atoms to make 2g of the sample.

7 0
3 years ago
A solution in which 50 grams of solute is dissolved in 250 grams of solution has a concentration of blank percent.
Stella [2.4K]

Answer:

20%

Explanation:

w=(solute)/(solution)

w = 50g/250g = 0.2

6 0
4 years ago
Name at least three physical properties of the bowling ball?
Contact [7]

Answer:

A bowling ball is a ball that is used in the game of bowling, where you roll the ball down an aisle and try to knock down as many pins as you can.

7 0
4 years ago
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