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2 years ago

How many atoms are in a sample of 72.8 g calcium (Ca)?

2 answers:

8 0

Atomic mass Ca=40.078 a.m.u

40.078 g--------------------6.02x10²³ atoms
72.8 g ---------------------- ??

72.8 x (6.02x10²³ ) / 40.078 =

4.38x10²⁵ / 40.078 = 1.093x10²⁴ atoms

HOPE THIS HELPED :D

xxMikexx [17]2 years ago

5 0

Atomic mass Ca = 40.078 a.m.u

40.078 g -------------------- 6.02x10²³ atoms
72.8 g ---------------------- ??

72.8 x ( 6.02x10²³) / 40.078 =

4.38x10²⁵ / 40.078 = 1.093x10²⁴ atoms

hope this helps!

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Partner Namets) For each of the following reactions carried out: Write the balanced chemical equation, the full ionic equation,

torisob [31]

Answer : The full balanced ionic equation will be,

$2KI(aq)+Pb(NO_3)_2(aq)\rightarrow 2KNO_3(aq)+PbI_2(s)$

Reactants are lead nitrate and potassium iodide.

Products are lead iodide and potassium nitrate.

The spectator ions are, $K^+,NO_3^-$

Explanation :

Complete ionic equation : In complete ionic equation, all the substance that are strong electrolyte and present in an aqueous are represented in the form of ions.

Net ionic equation : In the net ionic equations, we are not include the spectator ions in the equations.

Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.

When potassium iodide react with lead nitrate then it gives potassium nitrate and lead iodide as a product.

The full balanced ionic equation will be,

$2KI(aq)+Pb(NO_3)_2(aq)\rightarrow 2KNO_3(aq)+PbI_2(s)$

The ionic equation in separated aqueous solution will be,

$2K^+(aq)+2I^{-}(aq)+Pb^{2+}(aq)+2NO_3^{-}(aq)\rightarrow PbI_2(s)+2K^+(aq)+2NO_3^{-}(aq)$

In this equation, $K^+\text{ and }NO_3^-$ are the spectator ions.

By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.

The net ionic equation will be,

$Pb^{2+}(aq)+2I^{-}(aq)\rightarrow PbI_2(s)$

4 0

3 years ago

Why do atoms gain or lose electrons?

Aleksandr [31]

Answer:kapil

Explanation:

Atoms lose electrons, if an electron gets more energy than then binding energy of the electron. This may be because of a collision with a charged particle or because of absorbtion of a photon. In a metal, there are just other positive charges nearby. The electron is not lost, but shared.

6 0

2 years ago

How many grams of NaCl are in 2.0 Liters of a 3.0 M NaCl solution?

Naddik [55]

Answer:

350.64g

Explanation:

So first you must know that M is mol/L

Next solve the problem using dimensional analysis

2L NaCl (3 mol/L) = 6 mol NaCl

After you got the number of moles you should look at your periodic table to find the molar mass

I see that it's 58.44g/mol

Use dimensional analysis again!

6 mol (58.44g/mol) = 350.64g

Don't forget to make me brainliest!

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2 years ago

A certain hydrocarbon has a molecular formula of C9H16. Which of the following is not a structural possibility for this hydrocar

snow_tiger [21]

Answer: Option (d) is the correct answer.

Explanation:

It is given that molecular formula is $C_{9}H_{16}$ . Now, we will calculate the degree of unsaturation as follows.

Degree of unsaturation = $C_{n} - \frac{\text{monovalent}}{2} + \frac{\text{trivalent}}{2} + 1$

= $9 - \frac{16}{2} + 1$

= 9 - 8 + 1

= 2

As the degree of unsaturation comes out to be 2. It means that this compound will contain one ring and one double bond.

Yes, this compound could be an alkyne as for alkyne D.B.E = 2.

But this compound cannot be a cycloalkane because for a cycloalkane D.B.E = 1 which is due to the ring only.

Thus, we can conclude that it is a cycloalkane is not a structural possibility for this hydrocarbon.

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2 years ago

Helpppp fasttttttttttttttt Choose the best word to complete the sentence.

Lapatulllka [165]

Answer:

equilateral (B)

Explanation:

it is the only word which relates to triangles and their shape - plus, its logical and makes sense.

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2 years ago