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3 years ago

When Mendeleev started his work on organizing the elements, about how many had

Chemistry

1 answer:

Talja [164]3 years ago

8 0

Answer:

About 60.

Explanation:

Mendeleev knew of 63 elements. He wrote their properties on cards and arranged them in order of atomic mass.

That's how he discovered that the properties of elements are periodic functions of their atomic masses.

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A can of butane with a pressure of 2 atm at 283k has its pressure increased to a new pressure of 5 atm. What is the temperature

Ber [7]

Answer:

New temperature T2 = 707.5 K (Approx.)

Explanation:

Given:

Old pressure P1 = 2 atm

Old temperature T1 = 283 K

New Pressure P2 = 5 atm

Find:

New temperature T2

Computation:

Using Gay-Lussac law;

P1 / T1 = P2 / T2

So,

2 / 283 = 5 / T2

New temperature T2 = 707.5 K (Approx.)

6 0

3 years ago

What best describes why hair gel is considered a noncrystalline solid?

ad-work [718]

Given what we know, we can confirm that hair gel is considered a noncrystalline solid due to Atoms in the hair gel having no particular order or pattern.

<h3>What is a noncrystalline solid?</h3>

This is a solid whose atoms are amorphous.
What this means is that the atoms lack a specific order like most solids.
The most common example of this is glass.

Therefore, given the definition of a noncrystalline solid as a solid whose atoms lack a specified order, we can confirm that the second option which states that "Atoms in the hair gel having no particular order or pattern" is correct.

To learn more about Atoms visit:

brainly.com/question/13981855?referrer=searchResults

3 0

3 years ago

How many atoms are in 5.76 moles of aluminum?

mariarad [96]

Answer:The number of atoms in 2.0 mole Al is A. 2.0 Al atoms. B. 3.0 x 1023 Al atoms.

Secondly, is aluminum an atom or molecule? Aluminum is the second element in the thirteenth column of the periodic table. It is classified as a post-transition metal and a "poor metal". Aluminum atoms contain 13 electrons and 13 protons. There are 3 valence electrons in the outer shell.

7 0

2 years ago

The isomers butane and methyl propane have

madreJ [45]

Explanation:

“The isomers butane and methyl propane have the same molecular formula and different properties”, this is because structural isomers usually have different properties to their parent.

3 0

3 years ago

The reaction for photosynthesis producing glucose sugar and oxygen gas is:

Anvisha [2.4K]

1.5 grams of glucose is produced from 2.20 g of CO₂.

To find the mass of glucose produced, first you must know the balanced reaction. For this, the Law of Conservation of Matter is followed.

The law of conservation of matter states that since no atom can be created or destroyed in a chemical reaction, the number of atoms that are present in the reagents has to be equal to the number of atoms present in the products.

So, in this case, the balanced reaction is:

6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the amounts of moles of each reactant and product participate in the reaction:

CO₂: 6 moles
H₂O: 6 moles
C₆H₁₂O₆: 1 mole
O₂: 6 moles

So, you know that 2.20 g of CO₂ react, whose molar weight is 44.01 g/mole. By definition of molar mass, 1 mole of CO₂ has 44.01 g. So, the number of moles that 2.20 grams of the compound represent is calculated as:

$moles of CO_{2} =2.20 grams*\frac{1 mole}{44.01 grams}$

moles of CO₂= 0.05 moles

Now you must follow the following rule of three: if by stoichiometry of the reaction 6 moles of CO₂ produce 1 mole of C₆H₁₂O₆, 0.05 moles of CO₂ produce how many moles of C₆H₁₂O₆?

$moles of C_{6} H_{12} O_{6} =\frac{0.05moles of CO_{2} *1 mole of C_{6} H_{12} O_{6}}{6moles of CO_{2}}$

moles of C₆H₁₂O₆= 8.33*10⁻³

Being the molar mass of glucose 180.18 g/mole, the mass that 8.33*10⁻³ moles of the compound represent is calculated as:

$mass of glucose =8.33*10^{-3} moles*\frac{180.18 grams}{1 mole}$

mass of glucose= 1.5 grams

Then, 1.5 grams of glucose is produced from 2.20 g of CO₂.

5 0

3 years ago