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2 years ago

True or false: atoms are electrically neutral; that is they do not have a charge.

1 answer:

3 0

Its true, By definition, an atom is electrically neutral<span> it has the same number of protons as it does electrons, plus some number of neutrons depending on the isotope</span>

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How many milliliters of a 3.4 M NaCl solution would be needed to prepare each solution?

Ksenya-84 [330]

Answer:

a. Approximately $1.3\; \rm mL$ .

b. Approximately $7.2\; \rm mL$ .

Explanation:

The unit of concentration " $\rm M$ " is equivalent to " $\rm mol \cdot L^{-1}$ ", which means "moles per liter."

However, the volume of both solutions were given in mililiters $\rm mL$ . Convert these volumes to liters:

$\displaystyle 45\; \rm mL = 45\; \rm mL \times \frac{1\; \rm L}{1000\; \rm mL} = 0.045\; \rm L$ .

$\displaystyle 330\; \rm mL = 330\; \rm mL \times \frac{1\; \rm L}{1000\; \rm mL} = 0.330\; \rm L$ .

In a solution of volume $V$ where the concentration of a solute is $c$ , there would be $c \cdot V$ (moles of) formula units of this solute.

Calculate the number of moles of $\rm NaCl$ formula units in each of the two solutions:

Solution in a.:

$n = c \cdot V = 0.045\; \rm L \times 0.10\; \rm mol \cdot L^{-1} = 0.0045\; \rm mol$ .

Solution in b.:

$n = c \cdot V = 0.330\; \rm L \times 0.074\; \rm mol \cdot L^{-1} = 0.02442\; \rm mol$ .

What volume of that $3.4\; \rm M$ (same as $3.4 \; \rm mol \cdot L^{-1}$ ) $\rm NaCl$ solution would contain that many

For the solution in a.:

$\displaystyle V = \frac{n}{c} = \frac{0.0045\; \rm mol}{3.4\; \rm mol \cdot L^{-1}} \approx 0.0013\; \rm L$ .

Convert the unit of that volume to milliliters:

$\displaystyle 0.0013\; \rm L = 0.0013\; \rm L \times \frac{1000\; \rm mL}{1\; \rm L} = 1.3\; \rm mL$ .

Similarly, for the solution in b.:

$\displaystyle V = \frac{n}{c} = \frac{0.02442\; \rm mol}{3.4\; \rm mol \cdot L^{-1}} \approx 0.0072\; \rm L$ .

Convert the unit of that volume to milliliters:

$\displaystyle 0.0072\; \rm L = 0.0072\; \rm L \times \frac{1000\; \rm mL}{1\; \rm L} = 7.2\; \rm mL$ .

8 0

2 years ago

calculate the number of moles of sulfuric acid that is contained in 250 mL of 8.500 M sulfuric acid solution

san4es73 [151]

Answer : The moles of $H_2SO_4$ are, 2.125 mole.

Explanation : Given,

Molarity of $H_2SO_4$ = 8.500 M

Volume of solution = 250 mL = 0.250 L (1 L = 1000 mL)

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

$\text{Molarity}=\frac{\text{Moles of }H_2SO_4}{\text{Volume of solution (in L)}}$

Now put all the given values in this formula, we get:

$8.500M=\frac{\text{Moles of }H_2SO_4}{0.250L}$

$\text{Moles of }H_2SO_4=2.125mol$

Therefore, the moles of $H_2SO_4$ are, 2.125 mole.

5 0

2 years ago

Explain using balanced chemical equations, the alkaline hydrolysis reaction of esters.

ser-zykov [4K]

Answer:

The alkaline hydrolysis of ester is known as saponification. When ester is heated with aqueous NaOH, sodium salt of acid and alcohol are formed.

3 0

2 years ago

Which is a statement of cell theory? All cells are made up of living molecules. All plants are made of cells. All animals are ma

erastovalidia [21]

Answer:

all cells are produced from other preexisting cells through cell division

4 0

3 years ago

Explain how to determine the number of neutrons an

oee [108]

To find the neutrons you add the mass number and the atomic number for neutrons

Hope this helps

-Zayn Malik

5 0

2 years ago

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