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3 years ago

Please help me complete the following table

Chemistry

1 answer:

Tasya [4]3 years ago

5 0

Answer:

1.) Atomic No. 19

No. of proton 19

No. of electron 19

symbol 39K19

2.) Atomic no. 26

Mass No. 56

No. of proton 26

Symbol 56Fe26

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In an experiment, 132 grams of potassium bromide (KNO3) was dissolved in 100 grams of water at 70 °C in 1 minute. Which of the f

pishuonlain [190]

Answer: A fewer number of particles of the sample will dissolve in 1 minute.

That is because normally the solubility and rate of solubility of the salts in water increase with the temperature. This is, the higher the temperature the higher and faster the number of particles that the water can dissolve. So, at 70°C more particles will be dissolved in water in 1 minute than at 20°C.

7 0

3 years ago

Read 2 more answers

Express in scientific notation. Make sure your answer has the same number of significant figures as the starting value. (6.0 x 1

Greeley [361]

I believe the correct answer from the choices listed above is the second option. The expression (6.0 x 104) (3.1 x 10-1) is equal to 1.9 x 10^4. We only have two significant figures from the starting expression that is why we rounded of the product from 1.86 to 1.9.

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3 years ago

Find the mass of 3.27 x 10^23 molecules of H2SO4. Use 3 significant digits 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

Which of these mixtures would best be separated through distillation

Andrew [12]

Answer: Water and acetone

Explanation: you will find that the water and the soil are polar opposite, while the principal component of the water are Hydrogen and Oxygen, in the acetone you will find a change of carbon, the components from each molecule confer to each one specific physical properties for example the boiling point, and the distillation is a physical separation based on the boiling point.

then you can find the boiling point of the water in 100 °C, and the boiling point of the acetone is 56 °C, this give as a difference of 44 °C,

then while the acetone is boiling the water is liquid state, and this give us the opportunity to the separate the acetone in gas state by condensation after the boiling.

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3 years ago

Anexample of a weak acidis OH SO. OH

dolphi86 [110]

Citric acid
Ethanoic acid
Methanoic acid
Lactic acid

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4 years ago