What is the term for metabolic pathways that use ATP to synthesize complex molecules from smaller components?

Why is it better to conduct an experiment more than once?

lilavasa [31]

The first reason to repeat experiments is simply to verify results. Different science disciplines have different criteria for determining what good results are. Biological assays, for example must be done in at least triplicate to generate acceptable data. Science is built on the assumption that published experimental protocols are repeatable.

2) The next reason to repeat experiments is to develop skills necessary to extend established methods and develop new experiments. “Practice make perfect” is true for the concert hall and the chemical laboratory.

3) Refining experimental observations is another reason to repeat. Maybe you did not follow the progress of the reaction like you should have.

4) Another reason to repeat experiments is to study and/or improve them in way. In the synthetic chemistry laboratory, for example, there is always a desire to improve the yield of a synthetic step. Will certain changes in the experimental conditions lead to a better yield? The only way to find out is to try it! The scientific method informs us that it is best to only make one change at a time.

5) The final reason to repeat an extraction, chromatographic or synthetic protocol is to produce more of your target substance. This is sometimes referred to scale-up.

8 0

3 years ago

the pressure in a sealed plastic container is 108 kPa at 41 degrees Celsius. What is the pressure when the temperature drops to

Katarina [22]

<u>Answer:</u> The new pressure will be 101.46 kPa.

<u>Explanation:</u>

To calculate the new pressure, we use the equation given by Gay-Lussac Law. This law states that pressure is directly proportional to the temperature of the gas at constant volume.

The equation given by this law is:

$\frac{P_1}{T_1}=\frac{P_2}{T_2}$

where,

$P_1\text{ and }T_1$ are initial pressure and temperature.

$P_2\text{ and }T_2$ are final pressure and temperature.

We are given:

By using conversion factor: $T(K)=T(^oC)+273$

$P_1=108kPa\\T_1=41^oC=314K\\P_2=?kPa\\T_2=22^oC=295K$

Putting values in above equation, we get:

$\frac{108kPa}{314K}=\frac{P_2}{295K}\\\\P_2=101.46kPa$

Hence, the new pressure will be 101.46 kPa.

3 0

3 years ago

Try to rationalize the sign of ΔS∘rxn in each case.

bonufazy [111]

Answer:

a) decrease, gas

b) increase, gas

c) liquid

d) increase, solid

Explanation:

Entropy refers to the degree of disorderliness of a system. If the number of moles of gas increases from left to right in a reaction, the entropy of the system increases positively.

Similarly, when the number of liquid molecules remain constant, there could only be a very little increase in entropy.

However, solids have the least entropy and the entropy of a system decreases when a system yields solid products.

6 0

3 years ago

Methyl salicylate is a common active ingredient in liniments such as ben-gay. It is also known as oil of wintergreen. It is made

arlik [135]

Answer: The empirical formula is $C_3H_3O$ .

Explanation:

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

$C_xH_yO_z+O_2\rightarrow CO_2+H_2O$

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of $CO_2$ = 12.24 g

Mass of $H_2O$ = 2.505 g

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 12.24 g of carbon dioxide, = $\frac{12}{44}\times 12.24=3.338g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 2.505 g of water, = $\frac{2}{18}\times 2.505=0.278g$ of hydrogen will be contained.

Mass of oxygen in the compound = (5.287) - (3.338+0.278) = 1.671 g

Step 1 : convert given masses into moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{3.338g}{12g/mole}=0.278moles$

Moles of H= $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.278g}{1g/mole}=0.278moles$

Moles of O= $\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{1.671g}{16g/mole}=0.104moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{0.278}{0.104}=3$

For H = $\frac{0.278}{0.104}=3$

For O = $\frac{0.104}{0.104}=1$

The ratio of C : H : O = 3: 3: 1

Hence the empirical formula is $C_3H_3O$ .

5 0

3 years ago

How many electrons in an atom could have these sets of quantum numbers n=7 l=3 ml=-1?

zysi [14]

Solution:

Since we have ml=-1

it shows that it has two 2e- i;e it fond in 2nd subshell in f orbital. And each subshell can hold 2 e-.

Thus the required answer is 2 electrons hold by an atom.

4 0

3 years ago