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3 years ago

A 250ml aqueous solution contains 45.1microgram of pesticide.express the pesticide concentration in:

Chemistry

1 answer:

olchik [2.2K]3 years ago

3 0

Answer:

1. 1.80x10⁻⁵ (w/w %).

2. 1.80x10⁻⁴ parts per thousand

3. 0.18 parts per million

Explanation:

The solution contains 45.1μg / 250mL.

1. Weight percent (100 times mass in grams of solute per gram of solution, as there are 250mL of water = 250g):

45.1x10⁻⁶g / 250g * 100 =

2. Parts per thousand (mg of solute per g of solution).

45.1μg * (1x10⁻³mg / 1μg) = 0.0451mg.

0.0451mg / 250g =

<h3>1.80x10⁻⁴ parts per thousand</h3>

3. Parts per million (μg of solute per g of solution):

45.1μg / 250g =

<h3>0.18 parts per million</h3>

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Given the reaction: solid sodium reacts with chlorine gas to form solid sodium chloride How many moles of the product result fro

lyudmila [28]

Answer:

number of moles of NaCl produce = 12 mol

Explanation:

Firstly, we need to write the chemical equation of the reaction and balance it .

Na(s) + Cl2(g) → NaCl(s)

The balanced equation is as follows:

2Na(s) + Cl2(g) → 2NaCl(s)

1 mole(71 g) of chlorine produces 2 moles(117 g) of sodium chloride

6 mole of chlorine gas will produce ? mole of sodium chloride

cross multiply

number of moles of NaCl produce = 6 × 2

number of moles of NaCl produce = 12 moles

number of moles of NaCl produce = 12 mol

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3 years ago

How many moles of copper are present in a sample that contains 4.55 x 10^24 atoms of copper

FinnZ [79.3K]

Hope you could understand.

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1 year ago

The concentration of protein in a urine sample is calculated to be 2.77 μg/mL. What is the concentration of this solution in uni

maxonik [38]

Answer:

The concentration of this solution in units of pounds per gallon is $2.776*10^{-5} \frac{lb}{gal}$

Explanation:

Units of measurement are established models for measuring different quantities. The conversion of units is the transformation of a quantity, expressed in a certain unit of measure, into an equivalent one, which may or may not be of the same system of units.

In this case, the conversion of units is carried out knowing that 1 μg are equal to 2.205*10⁻⁹ Lb and 1 mL equals 0.00022 Gallons. So

$2.77 \frac{ug}{mL} = \frac{2.77 ug}{mL}$

If 1 μg equals 2.205*10⁻⁹ lb, 2.77 μg how many lb equals?

$lb=\frac{2.77ug*2.205*10^{-9}lb }{1ug}$

lb=6.10785*10⁻⁹

So, 2.77 μg= 6.10785*10⁻⁹ lb

Then:

$2.77 \frac{ug}{mL} = \frac{2.77 ug}{mL}=\frac{6.10785*10^{-9}lb }{mL} =\frac{6.10785*10^{-9}lb }{0.00022 gal} =\frac{6.10785*10^{-9}lb }{0.00022 gal}$

You get:

$2.77 \frac{ug}{mL} = 2.776*10^{-5} \frac{lb}{gal}$

<u><em>The concentration of this solution in units of pounds per gallon is </em></u> $2.776*10^{-5} \frac{lb}{gal}$ <u><em></em></u>

6 0

2 years ago

Element A has 15 protons. Determine the number of neutrons in its isotope with mass number 33.

bagirrra123 [75]

In an electrically neuteral atom, number of protons = number of electrons = atomic number.
Mass number = neutrons + protons/electrons/atomic number
Therefore,
neutrons = mass number - <span>protons/electrons/atomic number
Neutrons = 33 - 15 = 18

The answer is thus B. But this is the solution and explanation along with it as proof.</span>

6 0

3 years ago

A 1.0 L volume of gas at 27.0°C exerts a pressure of 85.5 K PA what will the pressure be at 127°C assume constant volume

Marianna [84]

Answer:

114 kPa

Explanation:

Using Gay-Lussac's law you get the equation $\frac{P1}{T1} x \frac{P2}{T2}$ and converting celcius you get the final equation of $\frac{85.5}{27+273} x \frac{P2}{127+273}$ . After dividing 85.5 by 27+273(300) you get 0.285 and then you multiply 0.285 by 127+273 (400). You finally get 114 kPa

4 0

2 years ago