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3 years ago

How many elements are there?

Chemistry

2 answers:

s344n2d4d5 [400]3 years ago

6 0

There are 118 elements currently on the periodic table.

svlad2 [7]3 years ago

5 0

Answer:

118 is your answer!

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b. Imagine an unusual life form in which the N atom in an amino acid is changed to a C atom. Could a hydrogen bond in this unusu

musickatia [10]

Answer: No hydrogen bond cannot occur in this alpha helix structure.

Explanation: For hydrogen bond to form, the electronegativity difference should be more than 1.7. carbon has an electronegativity of 2.5 whereas hydrogen has 2.1 so their electronegativity difference is 0.3. So in this alpha helix structure cannot occur.

5 0

3 years ago

Consider the reaction of 35.0 g of iron as follows:

77julia77 [94]

Explanation:

4Fe + 3O2 --> 2Fe2O3

Mass of iron = 35g

How many moles of iron react?

The relationship between mass and moles is given as;

Moles = mass / Molar mass

Molar mass of iron = 56g/mol

Number of moles = 35 / 56 = 0.625 mol

How many moles of oxygen molecules must react?

From the equation of the reaction;

4 mol of Fe reacts with 3 mol of Oxygen molecule

0.625 mol would react with x mol?

4 = 3

0.625 = x

x = 0.625 * 3 / 4 = 0.46875 mol

How many moles of product form?

From the equation of the reaction;

4 mol of Fe reacts to form 2 mol of Fe2O3

0.625 mol would form x mol of Fe2O3

4 = 2

0.625 = x

x = 0.625 * 2 / 4 = 0.3125 mol

What mass of product forms?

Moles = mass / Molar mass

Mass = Molar mass * Moles = 159.69 g/mol * 0.3125 mol = 49.9g

8 0

4 years ago

What are the gas laws? (Include Boyle's law, charles's law, gay lussac's law, an avogadro's law) Could someone please summarize

Rina8888 [55]

Answer:

Boyle's Law: When the pressure of a gas increases, the volume of the gas will decrease as long as the temperature and amount of gas are constant.

So basically pressure is inversely proportional to Volume, when one increases, the other decreases, vice versa.

Equation: $P_{1} V_{1} = P_{2} V_{2}$

Charles Law: When the temperature of a gas increases, the volume of a gas will also increase if the pressure and amount of gas are constant.

So basically Temperature and volume are directly proportional.

Equation: $\frac{V_{1}}{T_{1}} = \frac{V_{2} }{T_{2} }$

Gay Lussac's Law: When the temperature of a gas increases, the pressure of a gas also increases when volume and the amount of gas remain constant.

Basically, Temperature and Pressure are directly proportional.

Equation: $\frac{P_{1}}{T_{1}} = \frac{P_{2} }{T_{2} }$

Avogadro's Law: The most intuitive gas law. When you increase the amount of gas, the volume will also increase.

Meaning the moles (amount of gas) is directly proportional to volume.

Equation: $\frac{V_{1} }{n_{1} } = \frac{V_{2} }{n_{2} }$ (n stands for moles)

There is a combined gas law and ideal gas law but those are just the gas laws mentioned above but combined together. These should be everything.

8 0

2 years ago

Read 2 more answers

What does the capital letter, such as T, represent in a punnett square

aleksklad [387]

Answer: A dominant gene.

Explanation:

4 0

3 years ago

Read 2 more answers

A chemist prepares a solution of aluminum sulfate (Al2(SO4) by weighing out 116.0 g of aluminum sulfate into a 450. mL volumetri

trasher [3.6K]

Answer:

0.0733 mol /dL

Explanation:

Mole -

Moles is denoted by given mass divided by the molecular mass ,

Hence ,

n = w / m

n = moles ,

w = given mass ,

m = molecular mass .

From the information of the question ,

w = 116.0 g

As we know, molecular mass of aluminum sulfate ,

m = 342.15 g/mol

n = w / m

n = 116.0 g / 342.15 g/mol = 0.33 mol

Molarity -

Molarity of a substance , is the number of moles present in a liter of solution .

M = n / V

M = molarity

V = volume of solution in liter ,

n = moles of solute ,

The unit is mol / L ,

Hence , from the question, the value of molarity is asked ,

From the information of the question ,

V = 450 mL ,

Since,

1 mL = 0.01 dL

As, the unit asked in the question is in dL,

V = 4.5 dL

n = 0.33 mol ( as calculated above )

Using the above formula ,

M = n / V

M = 0.33 mol / 4.5 dL

M = 0.0733 mol /dL

M =

5 0

4 years ago