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4 years ago

A

Chemistry

1 answer:

yuradex [85]4 years ago

7 0

Answer:

the answer is (2.54cm in an inch, and 4 number of choices in this question)

Explanation:

An exact number is not rounded, and cannot be changed such as placing a different item on the scale it would change.

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What is the meaning of nucleus<br>

IrinaVladis [17]

the nucleus is an organelle containing the cell's chromosomes

8 0

3 years ago

Find the mass of 3.27 x 10^23 molecules of H2SO4. Use 3 significant digits<br> and put the units.

marta [7]

Answer:

Approximately $53.3\; \rm g$ .

Explanation:

Lookup Avogadro's Number: $N_{\rm A} = 6.02\times 10^{23}\; \rm mol^{-1}$ (three significant figures.)

Lookup the relative atomic mass of $\rm H$ , $\rm S$ , and $\rm O$ on a modern periodic table:

$\rm H$ : $1.008$ .
$\rm S$ : $32.06$ .
$\rm O$ : $15.999$ .

(For example, the relative atomic mass of $\rm H$ is $1.008$ means that the mass of one mole of $\rm H\!$ atoms would be approximately $1.008\!$ grams on average.)

The question counted the number of $\rm H_2SO_4$ molecules without using any unit. Avogadro's Number $N_{\rm A}$ helps convert the unit of that count to moles.

Each mole of $\rm H_2SO_4$ molecules includes exactly $(1\; {\rm mol} \times N_\text{A}) \approx 6.02\times 10^{23}$ of these $\rm H_2SO_4 \!$ molecules.

$3.27 \times 10^{23}$ $\rm H_2SO_4$ molecules would correspond to $\displaystyle n = \frac{N}{N_{\rm A}} \approx \frac{3.27 \times 10^{23}}{6.02 \times 10^{23}\; \rm mol^{-1}} \approx 0.541389\; \rm mol$ of such molecules.

(Keep more significant figures than required during intermediary steps.)

The formula mass of $\rm H_2SO_4$ gives the mass of each mole of $\rm H_2SO_4\!$ molecules. The value of the formula mass could be calculated using the relative atomic mass of each element:

$\begin{aligned}& M({\rm H_2SO_4}) \\ &= (2 \times 1.008 + 32.06 + 4 \times 15.999)\; \rm g \cdot mol^{-1} \\ &= 98.702\; \rm g \cdot mol^{-1}\end{aligned}$ .

Calculate the mass of approximately $0.541389\; \rm mol$ of $\rm H_2SO_4$ :

$\begin{aligned}m &= n \cdot M \\ &\approx 0.541389\; \rm mol \times 98.702\; \rm g \cdot mol^{-1}\\ &\approx 53.3\; \rm g\end{aligned}$ .

(Rounded to three significant figures.)

6 0

3 years ago

How is beryllium similar to calcium?<br>

Molodets [167]

Answer:

The second column on the periodic table of the chemical elements is collectively called the alkaline earth metal group: beryllium, magnesium, calcium, strontium, barium, and radium. Because the outer electron structure in all of these elements is similar, they all have somewhat similar chemical and physical properties.

Explanation:

8 0

3 years ago

What was the key characteristic by which Dmitri Mendeleev arranged his periodic table? A. increasing atomic number B. electron c

valentina_108 [34]

I think the correct answer from the choices listed above is option A. The key characteristic by which Dmitri Mendeleev arranged his periodic table was that the elements are arranged in increasing atomic number. Hope this answers the question.

4 0

3 years ago

Read 2 more answers

alculate the molarity of a solution that contains 20.0grams of sodium hydroxide in 200. ml of solution.

valentina_108 [34]

The molarity of a solution that contains 20.0grams of sodium hydroxide in 200. ml of solution is 2.3 M.

<h3>What is Molarity? </h3>

Molarity is defined as the ratio of number of moles of solute to the volume of the solution.

Molarity = number of moles of solute/ Volume of solution

Given,

given mass of sodium hydroxide= 20 g

Volume of the solution = 200 mL.

Firstly, we will calculate the moles of sodium hydroxide.

Mole is defined as the ratio of given mass of substance to the molar mass of substance.

Mole = given mass/ molar mass

Molar mass of sodium hydroxide = 40 g

Mole = 20/40

= 0.5 mol

Molarity = (0.5/ 200) × 1000 = 2.5M

Thus, we calculated that the molarity of a solution that contains 20.0grams of sodium hydroxide in 200. ml of solution is 2.3 M.

learn more about Molarity:

brainly.com/question/19517011

#SPJ4

5 0

2 years ago