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Novosadov [1.4K]
2 years ago
5

A first-order reaction has a half-life of 16.7 s . How long does it take for the concentration of the reactant in the reaction t

o fall to one-fourth of its initial value?
Chemistry
1 answer:
andrew11 [14]2 years ago
5 0

It takes 33.4 s for the concentration of A to fall to one-fourth of its original value.

A <em>half-life</em> is the time it takes for the concentration to fall to half its original value.

Assume the initial concentration is 1.00 mol/L. Then,

\text{1.00 mol/L }\stackrel{\text{1st half-life }}{\longrightarrow}\text{ 0.50 mol/L } \stackrel{\text{ 2nd half-life }}{\longrightarrow}\text{0.25 mol/L}\\

The concentration drops to one-fourth of its initial value in two half-lives.

∴ Time = 2 × 16.7 s = 33.4 s

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Identify the reactants and the products in this chemical equation.<br><br> 2Fe2O3 + 3C → 4Fe + 3CO2
aivan3 [116]

Answer:

Fe₂O₃ and C are reactants

Fe and CO₂ are products

Explanation:

Reactants:

Chemical species that are present on left side of chemical reaction equation are called reactants.

Product:

Chemical species that are present on right side of chemical reaction equation are called product.

Chemical equation:

2Fe₂O₃ + 3C  →  4Fe + 3CO₂

In this reaction 2 mole of iron oxide is react with three moles of carbon and produced four moles of iron and three moles of carbon dioxide. There are equal numbers of atoms of all elements present on both side of chemical reaction so this reaction follow the law of conservation of mass.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

Explanation:

This law was given by french chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

7 0
3 years ago
If a 100. -g sample of a hydrated compound contains 37.07-g sodium, 48.39-g carbonate and 14.54-g water, find the empirical form
Mumz [18]

he required empirical formula based on the data provided is Na2CO3.H2O.

<h3>What is empirical formula?</h3>

The term empirical formula refers to the formula of a compound which shows the ratio of each specie present.

We have the following;

Mass of sodium = 37.07-g

Mass of carbonate = 48.39 g

Mass of water = 14.54-g

Number of moles of sodium = 37.07-g/23 g/mol = 2 moles

Number of moles of carbonate = 48.39 g/61 g/mol = 1 mole

Number of moles of water = 14.54/18 g/mol = 1 mole

The mole ratio is 2 : 1: 1

Hence, the required empirical formula is Na2CO3.H2O

Learn more about empirical formula : brainly.com/question/11588623

3 0
1 year ago
Classify each amino acid into the following categories. Select the amino acid that fits best in each category. Each amino acid w
mel-nik [20]

Answer:

1. Lysine

2. Aspartic acid

3. Serine

4. Alanine

5. Tryptophan

Explanation:

Amino acids are biomolecules that contain two functional groups and one R side chain. The two functional groups are: carboxyl group and amino group.

The α-amino acids are the amino acids in which the two functional groups and the R side chain are attached to the α-carbon of the amino acid. They are total 22 α-amino acids.

1. A basic amino acid: Lysine is a positively charged, polar basic amino acid with a lysyl side chain.

2. An acidic amino acid: Aspartic acid is a negatively charged, polar acidic amino acid with an acidic carboxymethyl group.

3. A neutral polar amino acid: Serine is a polar and neutral amino acid with a hydroxymethyl group.

4. A non-polar aliphatic amino acid: Alanine is an aliphatic, nonpolar and neutral amino acid with a methyl side chain.

5. An aromatic amino acid: Tryptophan is an aromatic, nonpolar and neutral amino acid with an indole side chain.

3 0
3 years ago
What did Zoya and her freind do in response
Mama L [17]
In response of what like what’s the full clear question
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3 years ago
I just don’t know what to do
ValentinkaMS [17]

Answer:

I dont know if this is correct.. but maybe in the tool row, put graduated cylinder because you use graduated cylinders to measure water and for units put milliliters or liters?? Sorry if this isnt correct i wouldnt know what else to put !

Explanation:

3 0
2 years ago
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