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4 years ago

Which of the following best describes an atom? For science

1 answer:

vladimir2022 [97]4 years ago

7 0

Answer:An atom consists of three sub atomic particles which are protons, neutrons, and electrons. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge.

Explanation: because atoms are made up of particles

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A car travels 500km in 9 hours. How fast was it going

Firdavs [7]

Answer:

about 55 kilometers per hour

Explanation:

distance divided by time = 500/9

6 0

3 years ago

Name the following Compound: CrF2

pav-90 [236]

Chromium(II) fluoride

8 0

3 years ago

Caffeine, a stimulant in coffee and tea, has a molar mass of 194.19 g/mol and a mass percentage composition of 49.48% C, 5.19% H

lozanna [386]

Answer : The molecular formula of a caffeine is, $C_8H_{10}N_4O_2$

Solution :

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C = 49.48 g

Mass of H = 5.19 g

Mass of N = 28.85 g

Mass of O = 16.48 g

Molar mass of C = 12 g/mole

Molar mass of H = 1 g/mole

Molar mass of N = 14 g/mole

Molar mass of O = 16 g/mole

Step 1 : convert given masses into moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{49.48g}{12g/mole}=4.12moles$

Moles of H = $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{5.19g}{1g/mole}=5.19moles$

Moles of N = $\frac{\text{ given mass of N}}{\text{ molar mass of N}}= \frac{28.85g}{14g/mole}=2.06moles$

Moles of O = $\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{16.48g}{16g/mole}=1.03moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{4.12}{1.03}=4$

For H = $\frac{5.19}{1.03}=5.03\approx 5$

For N = $\frac{2.06}{1.03}=2$

For O = $\frac{1.03}{1.03}=1$

The ratio of C : H : N : O = 4 : 5 : 2 : 1

The mole ratio of the element is represented by subscripts in empirical formula.

The Empirical formula = $C_4H_5N_2O_1=C_4H_5N_2O$

The empirical formula weight = 4(12) + 5(1) + 2(14) + 16 = 97 gram/eq

Now we have to calculate the molecular formula of the compound.

Formula used :

$n=\frac{\text{Molecular formula}}{\text{Empirical formula weight}}$

$n=\frac{194.19}{97}=2$

Molecular formula = $(C_4H_5N_2O)_n=(C_4H_5N_2O)_2=C_8H_{10}N_4O_2$

Therefore, the molecular of the caffeine is, $C_8H_{10}N_4O_2$

5 0

3 years ago

There are seven petals on that flower.<br> O<br> qualitative<br> quantitative

Dahasolnce [82]

Hey :)

This time the answer is quantitive because the mentions numbers

Hope this helps!

3 0

3 years ago

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What is one difference between a mixture and a compound?

saveliy_v [14]

The different substances are not chemically joined together , each substance in the mixture keeps its own properties different from the elements it contains each substance is easily separated from the mixture.<span />

3 0

4 years ago

Read 2 more answers