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Chemistry

2 answers:

VARVARA [1.3K]2 years ago

5 0

Answer:

number 4

Explanation:

sorry if wrong

anastassius [24]2 years ago

3 0

Answer:

Explanation:

in order for the bobber to float,it must be less dense, and for the line to sink, it must be more dense.

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What is the mass of a gold bar that is 7.379*10^-4 m^3 in volume?

NISA [10]

Mass to volume
M^3 --> cm^3
Cm^3 --> mL
Centi = 10*-2
7.379*10-4 / 1*10-2 = .07379

8 0

3 years ago

Changing subscripts is one of the steps of balancing a chemical equation. True or False

Lostsunrise [7]

Answer:

False

Explanation:

Changing the coefficients is one of the steps of balancing a chemical equation. Changing the subscript changes the compounds being used, while changing the coefficient changes the amount of each compound being used.

3 0

3 years ago

Read 2 more answers

Draw the product that valine forms when it reacts with excess CH3CH2OH and HCl followed by a wash with aqueous base.

-BARSIC- [3]

Answer:

Product: ethyl L-valinate

Explanation:

If we want to understand what it is the molecule produced we have to analyze the reagents. We have valine an amino acid, in this kind of compounds we have an amine group ( $NH_2$ ) and a carboxylic acid group ( $COOH$ ). Additionally, we have an alcohol ( $CH_3CH_2OH$ ) in the presence of HCl (a strong acid) in the first step, and a base ( $OH^-$ ).

When we have an acid and an alcohol in a vessel we will have an esterification reaction. In other words, an ester is produced. As the first step, the oxygen in the C=O (in the carboxylic acid group) would be protonated. In the second step, the ethanol attacks the carbon in the C=O of the carboxylic acid group producing a new bond between the oxygen in the ethanol and the carbon in the carboxylic acid. In step 3, a proton is transferred to produce a better leaving group ( $H_2O$ ). In step 4, a water molecule leaves the main structure to produce again the double bond C=O. Finally, a base ( $OH^-$ ) removes the hydrogen from the C=O bond to produce ethyl L-valinate