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3 years ago

Describe it what is the scientefic method??

Chemistry

1 answer:

WINSTONCH [101]3 years ago

5 0

It is the principles and procedures for the systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of hypotheses

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Put the following in the correct chronological order from what happened first to what happened last.

Scilla [17]

Answer:

2-3-1-4

Explanation:

The astronomer Nicolaus Copernicus did not have a theory about the Earth revolving around the sun until he got into astronomy and began to study the patterns of the sun and the moon as well as reading other entries from previous astronomers. You can pretty much guess from there, he had to have the theory before proving it etc.

3 0

3 years ago

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

See figure 1

I hope it helps!

7 0

4 years ago

Calculate the Cal(kcal) in 1 cup of whole milk: 12 g of carbohydrate, 9 g of fat, and 9 g of protein.

laiz [17]

Fat: 1 gram = 9 calories Protein: 1 gram = 4 calories Carbohydrates: 1 gram = 4 calories Alcohol: 1 gram = 7 calories"
So, (12 g carbohydrates)*4 Cal=48 Cal; (9 g fat) *9 Cal=81 Cal; (9 g protein)*4 Cal=36 Cal
48 Cal + 81 Cal + 36 Cal = 165 Cal in one glass of milk

5 0

4 years ago

Read 2 more answers

The vapor pressure of water is 1.00 atm at 373 K, and the enthalpy of vaporization is 40.68 kJ mol!. Estimate the vapor pressure

Yuki888 [10]

Answer:

The vapor pressure at temperature 363 K is 0.6970 atm

The vapor pressure at 383 K is 1.410 atm

Explanation:

To calculate $\Delta H_{vap}$ of the reaction, we use clausius claypron equation, which is:

$\ln(\frac{P_2}{P_1})=\frac{\Delta H_{vap}}{R}[\frac{1}{T_1}-\frac{1}{T_2}]$

where,

$P_1$ = vapor pressure at temperature $T_1$

$P_2$ = vapor pressure at temperature $T_2$

$\Delta H_{vap}$ = Enthalpy of vaporization

R = Gas constant = 8.314 J/mol K

1) $\Delta H_{vap}=40.68 kJ/mol=40680 J/mol$

$T_1$ = initial temperature =363 K

$T_2$ = final temperature =373 K

$P_2=1 atm, P_1=?$

Putting values in above equation, we get:

$\ln(\frac{1 atm}{P_1})=\frac{40680 J/mol}{8.314J/mol.K}[\frac{1}{363}-\frac{1}{373}]$

$P_1=0.69671 atm \approx 0.6970 atm$

The vapor pressure at temperature 363 K is 0.6970 atm

2) $\Delta H_{vap}=40.68 kJ/mol=40680 J/mol$

$T_1$ = initial temperature =373 K

$T_2$ = final temperature =383 K

$P_1=1 atm, P_2?$

Putting values in above equation, we get:

$\ln(\frac{P_2}{1 atm})=\frac{40680 J/mol}{8.314J/mol.K}[\frac{1}{373}-\frac{1}{383}]$

$P_2=1.4084 atm \approx 1.410 atm$

The vapor pressure at 383 K is 1.410 atm

8 0

3 years ago

What would happen if the oceanic plates stoped moving

Ket [755]

Answer:

But without plate tectonics, Earth will simply stop making new ones. The mountains we have now would erode over a few million years, turning into low, rolling hills. Our planet would eventually flatten out, with more land ending up underwater. On the bright side, there'd be fewer natural disasters.

Explanation:

that is what would happen

3 0

3 years ago

Read 2 more answers