Part of the experiment that is used as a comparison to see if they independent variable caused a change

Name the two criteria that is used to determine if a substance is pure or not

meriva

Answer:

Melting and Boiling Point Determination

The physical properties of a substance can be used to establish its purity. These properties include the melting point and boiling point. Different substances tend to have different melting and boiling points, and any pure substance will have a specific melting and boiling point.

3 0

3 years ago

The chemist discovers a more efficient catalyst that can produce ethyl butyrate with a 78.0 % yield. How many grams would be pro

zepelin [54]

7.66g of ethyl butyrate is produced.

The reaction is

CH₃CH₂CH₂COOH + CH₃CH₂OH ----> CH₃CH₂CH₂COOCH₂CH₃

The molar mass of butanoic acid is 88.11g/mol
We have 7.45g of butanoic acid
The moles of butanoic acid we have is 7.45/88.11 = 0.0845 mol
If the yield is 100%, 1 mole of butanoic acid gives 1 mole of ethyl butyrate
But the reaction yield is 78%
1 mole of butanoic acid gives 0.78 mole of ethyl butyrate

From 0.0845 mol of butanoic acid we get 0.78 x 0.0845 = 0.66 mol of ethyl butyrate.

The molar mass of ethyl butyrate is 116.16g/mol

So 0.66 x 116.16 = 7.66g

7.66g of ethyl butyrate is produced.

Learn more about esterification here:

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4 0

2 years ago

Which can form a double covalent bond? Cl H N Ca C O

stiv31 [10]

Answer:

Oxygen

Explanation:

First of all, let's remember that covalent bonds are formed between nonmetal atoms. Given the list of the atoms, calcium is the only metal (it belongs to group 2A, alkaline earth metals). This means calcium doesn't form covalent bonds, it forms ionic bonds. The remaining atoms are all nonmetals and form covalent bonds.

To avoid ambiguity and several choices possible for this problem, we'll assume that we're only talking about diatomic molecules (molecules consisting only of two atoms) in this question.

In covalent bonding, atoms join together to have their valence shells filled, that is, to have octets in their shells (except hydrogen which can only have up to 2 electrons in its shell). Let's look at how many bonds each of these nonmetals will form in a diatomic molecule:

Chlorine is in group 7A, it has 7 valence electrons, meaning it only needs 1 electron from a covalent bond to have an octet. This implies chlorine will have a single bond.
Hydrogen is in group 1A, it has 1 valence electron and the maximum it can have in its valence shell is 2 electrons, so it also lacks 1 electron that will be provided by the other atom in a single bond.
Nitrogen is in group 5A (it has 5 valence electrons). This means it needs 3 more to gain an octet, those would come from a triple bond.
Carbon is in group 4A (it has 4 valence electrons). It needs 4 more electrons to gain an octet. A quadruple bond would not be possible, the greatest carbon can make is a triple bond in CO having a lone pair remaining on carbon.
Oxygen is in group 6A (it has 6 valence electrons). It needs 2 more electrons to gain an octet. This implies it would make a double bond to obtain two more electrons from the other atom and acquire an octet.

7 0

4 years ago

PLEASE HELP 30 POINTS

Bas_tet [7]

Answer:

Because the rock is irregularly shaped, you used the displacement method to measure its volume. You used calculations to indirectly find the density of the objects.

PLZ Brainliest

8 0

3 years ago

A 0.100 M solution of chloroacetic acid 1ClCH2COOH2 is 11.0% ionized. Using this information, calculate 3ClCH2COO-4, 3H 4, 3ClCH

bearhunter [10]

Answer:

[CICH2COOH] = 0.089 M

[CICH2COO-] = 0.011 M

[H+] = 0.011 M

Ka = 1.36 x 10^-3

Explanation:

The reaction

CICH2COOH ⇄ H+ (aq) + CICH2COO- (aq)

The initial concentration of CICH2COOH is 0.10 M , chloroacetic acid is 11.0% ionized.

let us calculate Ka

First , find change in concentration

since , 11% ionized

change in concentration = 0.10 X 11% = 0.011 M

Initial Concentration of CICH2COOH = 0.10 M

change in concentration of CICH2COOH = - 0.011 M

Equilibrium Concentration of CICH2COOH = 0.10 M - 0.011 M = 0.089 m

Initial Concentration of CICH2COO- = 0 M

change in concentration of CICH2COO- = + 0.011 M

Equilibrium Concentration of CICH2COO- = 0.011 M

Initial Concentration of H+ = 0 M

change in concentration of H+ = + 0.011 M

Equilibrium Concentration of H+ = 0.011 M

Therefore,

[CICH2COOH] = 0.089 M

[CICH2COO-] = 0.011 M

[H+] = 0.011 M

Ka = [H+][CICH2COO-] /[CICH2COOH]

Ka = (0.011 * 0.011) / (0.089)

Ka = 1.36 x 10^-3

6 0

3 years ago