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vesna_86 [32]
2 years ago
15

6 + 9 = ? This is a tough question, my fellow friends...

Chemistry
2 answers:
Allushta [10]2 years ago
6 0

k k chill the answer is 15 sheesh...

vesna_86 [32]2 years ago
5 0

Answer:

uhmmmmmmmmmmmmmmmmm 15?

Explanation:

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Q 3.6: calculate the number of po43- ions present in 23.7 g of ca3(po4)2.
malfutka [58]
Moles of ca3(po4)2 = 23.7 / 310.17 =  0.076

moles of (PO4)3- = 0.076 x 2 = 0.152

now, no. of ions = 0.152 x 6.022 x 10^{23}

                          =  9.2 x 10^{22}
6 0
3 years ago
Read 2 more answers
What does the nucleus of the cell control?
dusya [7]

Answer:

Image result for What does the nucleus of the cell control?

The nucleus controls and regulates the activities of the cell (e.g., growth and metabolism) and carries the genes, structures that contain the hereditary information. Nucleoli are small bodies often seen within the nucleus.

Explanation:

7 0
2 years ago
a) Calculatethe molality, m, of an aqueous solution of 1.22 M sucrose, C12H22O11. The density of the solution is 1.12 g/mL.b) Wh
Contact [7]

Answer:

a) 1,74 molal

b) 37,2 %

c) 0,03

Explanation:

We are going to define sucrose as solute, water as solvent and the mix of both, the solution.

Let´s start with the data:

Molarity = M = \frac{1,22 mol solute}{lts solution}

We can assume as a calculus base, 1 liter of solution. So, in 1 liter of solution we have 1,22 moles of solute:

1 lts solution * \frac{1,22 moles solute}{lts solution}=1,22 moles solute

Knowing that the molality (m) is defined as mol of solute/kgs solvent, we have to calculate the mass of solvent on the solution. Remember our calculus base (1 lts of solution). In 1 lts of solution we have 1120 grams of solution.

1 lts solution * \frac{1,12 grs solution}{mL solution}*\frac{1000 mL solution}{1 lts solution} = 1120 grs of solution

With the molecular weight of solute (<em>Sum of: for carbon = 12*12=144; for hydrogen = 1*22=22 and for oxygen = 16*11=176. Final result = 342 grs per mol</em>), we can obtain the mass of solute:

1,22 mol solute*\frac{342 grs solute}{1 mol solute} = 417,24 grs solute

Now, the mass of solvent is: mass solvent = mass of solution - mass of solute. So, we have: 1120 - 417,24 = 702,76 grs of solvent = 0,70276 Kgs of solvent

molality = m = \frac{1,22 mol solute}{0,70276 kgs solvent}= 1,74 molal

For b) question we have that the mass percent of solute is hte ratio between the mass of solute and the mass of solution. So,

%(w/w) = \frac{417,24 grs solute}{1120 grs solution} = 37,2%

For c) question we have that the mole fraction of solute is the ratio between moles of solute and moles of solution. Let's calculate the moles of solution as follows: <em>Moles solution = moles solute + moles solvent.</em> First we have that the moles of solvent are (remember that the molecular weight of water for this calculus is 18 grs per mol):

702,76 grs solvent*\frac{1 mol solvent}{18 grs solvent} = 39,04 moles solvent  

So, we have the moles of solution: 1,22 moles of solute + 39,04 moles of solvent = 40,26 moles of solution

Finally, we have:

Mol frac solute = \frac{1,22 mol solute}{40,26 mol solution}= 0,03

6 0
3 years ago
An ion of iron has an 26 protons, 30 neutrons, and 23 electrons. What are its atomic number, atomic mass, and net charge?
sleet_krkn [62]

Answer:

Atomic number 26,atomic mass 26+30=56 dalton and net charge is 3+

Explanation:

The total number of proton present in an atom is known as the atomic number of that atom.From that point of view the atomic number of iron ion is 26.

  The total number proton and neutrons present in the nucleus of an atom or ion is termed as atomic mass.From that point of view the the atomic mass of iron ion is 26+30=56 dalton

 According to the given question iron ion contain 3 more protons than electrons as a result the iron ion will contain 3 unit positive charge.

5 0
3 years ago
How long will it take for a 750 mg sample of radium with a half life of 15 days to decay to exactly 68mg?
weqwewe [10]

Answer:

52 da  

Step-by-step explanation:

Whenever a question asks you, "How long to reach a certain concentration?" or something similar, you must use the appropriate integrated rate law expression.

The i<em>ntegrated rate law for a first-order reaction </em>is  

ln([A₀]/[A] ) = kt

Data:

[A]₀ = 750 mg

 [A] =    68 mg

t_ ½ =   15 da

Step 1. Calculate the value of the rate constant.

 t_½ = ln2/k     Multiply each side by k

kt_½ = ln2         Divide each side by t_½

      k = ln2/t_½

         = ln2/15

         = 0.0462 da⁻¹

Step 2. Calculate the time

ln(750/68) = 0.0462t

         ln11.0 = 0.0462t

            2.40 = 0.0462t     Divide each side by 0.0462

                   t = 52 da

8 0
3 years ago
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