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Sonbull [250]
3 years ago
5

12. How many moles of atoms are present in 154 g of Na2O?

Chemistry
1 answer:
tia_tia [17]3 years ago
6 0

Answer:

\boxed {\boxed {\sf A. \ 2.48 \ mol \ Na_2O}}

Explanation:

We are asked to convert an amount in grams to moles. To do this, we use the molar mass. This is the number of grams in one mole of a substance. It is the same value numerically as the atomic mass on the Periodic Table, however the units are grams per mole, not atomic mass units.

Look up the molar masses for the individual elements.

  • Sodium (Na): 22.9897693 g/mol
  • Oxygen (O): 15.999 g/mol

Look back at the formula: Na₂O. Notice there is a subscript of 2 after sodium. This means there are 2 atoms of sodium in every molecule, so we have to multiply sodium's molar mass by 2 before adding oxygen's.

  • Na₂O: 2(22.9897693 g/mol)+ 15.999 g/mol = 61.9785386 g/mol

Set up a ratio using the molar mass.

\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}

Multiply by the given number of grams.

154 \ g \ Na_2O*\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}

Flip the ratio so the grams of sodium oxide can cancel each other out.

154 \ g \ Na_2O*\frac {1  \ mol \ Na_2O}{61.9785386 \ g \ Na_2O}

154 *\frac {1  \ mol \ Na_2O}{61.9785386 }

\frac {154}{61.9785386 }  \ mol \ Na_2O

2.48473106141 \ mol \ Na_2O

The original measurement of grams given has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.

  • 2.48<u>4</u>73106141

The 4 in the thousandth place tells us to leave the 8.

2.48 \ mol \ Na_2O

There are <u>2.48 moles of sodium oxide</u> in 154 grams, so choice A is correct.

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monitta
The product of prime polynomials is equivalent to 36x3 – 15x2 – 6x is letter B which is 3x(3x – 2)(4x 1). Below is the solution. 

3x(3x - 2) (4x + 1)
= 9x2 - 6x (4x + 1)
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3 years ago
Question
andreev551 [17]

Answer:

Sln

n=m/mr

n=25/100

n=0.25mole of Caco3

Malality =number of moles/volume (divided by number of moles both sides)

volume =Malality /number of moles

v=0.125/0.25

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I hope this help

5 0
3 years ago
Steve walks from his house 5 I'm south then turns east and walks 2 km. Then he walks 9 in North to his older sister's house. She
IgorLugansk [536]

Answer:

18 km

Explanation:

To know the distance, you need to be clear in the concept of distance.

According to the physics, the distance is a measurement that refers to the fact of how much an object has move from one point to another.

In this case, we have a person named Steve and he's walking through several points.

To calculate the distance that he moved, you just need to sum all the values of distance. In this case, it's not neccesary to do calculations regarding the components of the x or y axis, because we are not talking about displacement, where it actually counts. But in this case, we just need all the covered distance that Steven walked since the beggining.

So, no more talk, let's do calculations:

D = 5 + 2 + 9 + 2 = 18 km

So the final answer would be:

<h2>Distance = 18 km</h2>

Hope this helps

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Answer:

yqaeh

Explanation:

Electrolysis of acidified water

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