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mash [69]
3 years ago
5

White blood cells, part of the ___________ system, work closely with the ___________ system to protect us from infection and dis

ease.
Chemistry
1 answer:
Kisachek [45]3 years ago
6 0

White blood cells, part of the <u>circulatory</u> system, work closely with the <u>Immune</u> system to protect us from infection and disease.

hope this helps :)

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Approximately how many formula units of NaCl are in 116.88g of table salt (NaCl), knowing that the molar mass of NaCl is 58.44g/
elena-14-01-66 [18.8K]

Answer:

116.88g of table salt (NaCl) contains two formula units

Explanation:

Now,

We know that 1 formula unit of sodium chloride has a molar mass of 58.44g/mol

Hence;

Mass of 1 formula unit = 58.44g

Mass of x formula units = 116.88g

x = 116.88g * 1 formula unit/58.44g

x = 2 formula units

Therefore;

116.88g of table salt (NaCl) contains two formula units

5 0
3 years ago
Read 2 more answers
How do core electrons relate to the ionization energy of the atom?
Archy [21]

Answer:

For any given element, ionization energy increases as subsequent electrons are removed. For example, the energy required to remove an electron from neutral chlorine is 1251 kJ/mol. ... An even sharper increase in ionization energy is witnessed when inner-shell, or core, electrons are removed.

Hope it helps :)

6 0
3 years ago
Combustion analysis of a 13.42-g sample of the unknown organic compound (which contains only carbon, hydrogen, and oxygen) produ
kirza4 [7]

<u>Answer:</u> The molecular formula for the given organic compound is C_{18}H_{20}O_2

<u>Explanation:</u>

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

C_xH_yO_z+O_2\rightarrow CO_2+H_2O

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of CO_2=39.61g

Mass of H_2O=9.01g

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

<u>For calculating the mass of carbon:</u>

In 44 g of carbon dioxide, 12 g of carbon is contained.

So, in 39.61 g of carbon dioxide, \frac{12}{44}\times 39.61=10.80g of carbon will be contained.

<u>For calculating the mass of hydrogen:</u>

In 18 g of water, 2 g of hydrogen is contained.

So, in 9.01 g of water, \frac{2}{18}\times 9.01=1.00g of hydrogen will be contained.

Mass of oxygen in the compound = (13.42) - (10.80 + 1.00) = 1.62 g

To formulate the empirical formula, we need to follow some steps:

  • <u>Step 1:</u> Converting the given masses into moles.

Moles of Carbon = \frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{10.80g}{12g/mole}=0.9moles

Moles of Hydrogen = \frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{1g}{1g/mole}=1moles

Moles of Oxygen = \frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{1.62g}{16g/mole}=0.10moles

  • <u>Step 2:</u> Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.10 moles.

For Carbon = \frac{0.9}{0.10}=9

For Hydrogen = \frac{1}{0.10}=10

For Oxygen = \frac{0.10}{0.10}=1

  • <u>Step 3:</u> Taking the mole ratio as their subscripts.

The ratio of C : H : O = 9 : 10 : 1

Hence, the empirical formula for the given compound is C_9H_{10}O

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is :

n=\frac{\text{Molecular mass}}{\text{Empirical mass}}

We are given:

Mass of molecular formula = 268.34 g/mol

Mass of empirical formula = 134 g/mol

Putting values in above equation, we get:

n=\frac{268.34g/mol}{134g/mol}=2

Multiplying this valency by the subscript of every element of empirical formula, we get:

C_{(9\times 2)}H_{(10\times 2)}O_{(1\times 2)}=C_{18}H_{20}O_2

Thus, the molecular formula for the given organic compound is C_{18}H_{20}O_2.

3 0
3 years ago
Isotopes are different types of atoms of the same element, but with a different number of __________ ?
rodikova [14]
Same things but with different numbers of neutrons in nuclei
6 0
3 years ago
Read 2 more answers
52° 31' 12.0288"N and 13° 24' 17.8344" E.<br> What continent is it on?
olga55 [171]

Answer: Europe

Explanation: it’s in germany

7 0
3 years ago
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