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3 years ago

How did Moseley establish a more accurate periodic table?

1 answer:

4 0

Moseley established a more accurate periodic table by closer determination of atomic numbers. Through the results of his measurements of the wavelengths of the X-ray spectral lines of a number of elements which showed that the ordering of the elements by atomic number.

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True or false: the density of an object can be calculated by dividing its length by its width.

solong [7]

This is true!!!!!!!!!!!!!!!!!!!!!!!!

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3 years ago

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Which body system processes food into a useable source of energy?

anastassius [24]

Answer:

Glucose, found in the food animals eat, is broken down during the process of cellular respiration into an energy source called ATP. When excess ATP and glucose are present, the liver converts them into a molecule called glycogen, which is stored for later use.

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3 years ago

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In an experiment, the molar mass of the compound was determined to

sasho [114]

Determine the mass in grams of each element in the sample. If you are given percent composition, you can directly convert the percentage of each element to grams.
For example, a molecule has a molecular weight of 180.18 g/mol. It is found to contain 40.00% carbon, 6.72% hydrogen and 53.28% oxygen.
Convert the percentages to grams.
40.00 grams of carbon
6.72 grams of hydrogen
53.28 grams of oxygen

3 0

3 years ago

Start with 100.00 mL of 0.10 M acetic acid, CH3COOH. The solution has a pH of 2.87 at 25 oC. a) Calculate the Ka of acetic acid

jasenka [17]

Answer: a) The $K_a$ of acetic acid at $25^0C$ is $1.82\times 10^{-5}$

b) The percent dissociation for the solution is $4.27\times 10^{-3}$

Explanation:

$CH_3COOH\rightarrow CH_3COO^-H^+$

cM 0 0

$c-c\alpha$ $c\alpha$ $c\alpha$

So dissociation constant will be:

$K_a=\frac{(c\alpha)^{2}}{c-c\alpha}$

Give c= 0.10 M and $\alpha$ = ?

Also $pH=-log[H^+]$

$2.87=-log[H^+]$

$[H^+]=1.35\times 10^{-3}M$

$[CH_3COO^-]=1.35\times 10^{-3}M$

$[CH_3COOH]=(0.10M-1.35\times 10^{-3}=0.09806M$

Putting in the values we get:

$K_a=\frac{(1.35\times 10^{-3})^2}{(0.09806)}$

$K_a=1.82\times 10^{-5}$

b) $\alpha=\sqrt\frac{K_a}{c}$

$\alpha=\sqrt\frac{1.82\times 10^{-5}}{0.10}$

$\alpha=4.27\times 10^{-5}$

$\% \alpha=4.27\times 10^{-5}\times 100=4.27\times 10^{-3}$

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3 years ago

Which of the following is true about neutralization reactions? Question 6 options: They involve strong acids and strong bases. T

EastWind [94]

The correct option is: ALL OF THE ABOVE.
A neutralization reaction is one in which acid and base react together in order to produce salt and water. The water formed is as a result of hydrogen ion and the hydroxyl ion which combine together to produce water. When a solution is neutralized, it implies that the salt is formed from equal weights of acid and base.

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3 years ago