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3 years ago

99.9% of the matter that makes up living organisms consist of how many elements

Chemistry

1 answer:

gulaghasi [49]3 years ago

7 0

Answer:

6 elements.

Explanation:

99.9% by weight of most living things is made of the six elements: hydrogen, carbon, nitrogen, oxygen, phosphorus, and sulfur (backwards using just the letter abbreviations this spells SPONCH).

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A solution of NaCl ( aq ) is added slowly to a solution of lead nitrate, Pb ( NO 3 ) 2 ( aq ) , until no further precipitation o

dezoksy [38]

Answer:

0.218 M of Pb(NO3)2

Explanation:

Equation of the reaction

Pb(NO3)2(aq) + 2NaCl(aq) --> PbCl2(s) + 2NaNO3(aq)

1 mole of Pb(NO3)2 reacts to precipitate 1 mole of PbCl2

Molar mass of PbCl2 = 207 + (35.5*2)

= 278 g/mol

Number of moles of PbCl2 precipitated = mass/molar mass

= 12.11/278

= 0.04356 mol

Since 0.04356 moles of PbCl2 was precipitated, therefore by stoichiometry; 0.04356 moles of Pb(NO3)2 reacted.

Molarity is defined as the number of moles of solute in 1 liter of solution.

Molarity = number of moles/volumes

= 0.04356/0.2

= 0.218 M

6 0

3 years ago

Are HF CH4 and CO2 acids or bases>

Vlad [161]

Huh I do not understand this

4 0

2 years ago

As discussed in class, the Fischer esterification reactants and products are at equilibrium. How was the equilibrium of the reac

german

Answer:

See explanation

Explanation:

The particular reactants in the Fischer esterification reaction were not stated.

Generally, a Fischer esterification is a reaction that proceeds as follows;

RCOOH + R'OH ⇄RCOOR' + H2O

This reaction occurs in the presence of an acid catalyst.

We can shift the equilibrium of this reaction towards the products side in two ways;

I) use of a large excess of either of the reactants

ii) removal of one of the products as it is formed.

Any of these methods shifts the equilibrium of the Fischer esterification reaction towards the products side.

4 0

3 years ago

If 100.0g of nitrogen is reacted with 100.0g of hydrogen, what is the excess reactant? What is the limiting reactant? Show your

Drupady [299]

N₂ : limiting reactant

H₂ : excess reactant

<h3>Further explanation</h3>

Given

mass of N₂ = 100 g

mass of H₂ = 100 g

Required

Limiting reactant

Excess reactant

Solution

Reaction

mol N₂(MW=28 g/mol) :

$\tt mol=\dfrac{mass}{MW}=\dfrac{100}{28}=3.571$

mol H₂(MW= 2 g/mol) :

$\tt mol=\dfrac{100}{2}=50$

A method that can be used to find limiting reactants is to divide the number of moles of known substances by their respective coefficients, and small or exhausted reactans become a limiting reactants

From the equation, mol ratio N₂ : H₂ = 1 : 3, so :

$\tt \dfrac{3.571}{1}\div \dfrac{50}{3}=3.571\div 16.6$

N₂ becomes a limiting reactant (smaller ratio) and H₂ is the excess reactant

5 0

2 years ago

What scientist designed an experiment that enabled the first successful detection of an individual subatomic particle?

damaskus [11]

Thomson<span> is the scientist who designed an experiment that enabled the first successful detection of an individual subatomic particle. </span>J.J. Thomson<span> (Sir </span>Joseph John Thomson<span>, 1856-1940), who demonstrated in 1897 that "cathode rays" consisted of negatively-charged particles, later named electrons.</span>

6 0

2 years ago