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2 years ago

Explain what happens to the imidazole side chain of histidine in a buffer of pH 4.0 and at pH 10.2.

1 answer:

4 0

Histidine, an essential amino acid, has as a positively charged imidazole functional group. The imidazole makes it a common participant in enzyme catalyzed reactions. The unprotonated imidazole is nucleophilic and can serve as a general base, while the protonated form can serve as a general acid.

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Scientist use alternative ways to seek out if a fault is active which one isn't include

dalvyx [7]

Answer:

Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,000 years. Active faulting is considered to be a geologic hazard - one related to earthquakes as a cause.

Explanation:

Plz mark brainliest thanks

3 0

2 years ago

How many formula units make up 36.0 g of magnesium chloride (MgCl2)?

zalisa [80]

Answer: There are $2.29\times 10^{23}$ formula units

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}=\frac{36.0g}{95g/mol}=0.38moles$

1 mole of $MgCl_2$ contains = $6.023\times 10^{23}$ formula units

Thus 0.38 moles of $MgCl_2$ contains = $\frac{6.023\times 10^{23}}{1}\times 0.38=2.29\times 10^{23}$ formula units

Thus there are $2.29\times 10^{23}$ formula units

6 0

3 years ago

The pictured compound has which of the following bonds?

Veseljchak [2.6K]

Answer: There are C - C bonds and C - H bonds.

trust me! I took a test with this question and got 100! :)

6 0

3 years ago

The half-life of sr-90 is 28 years. after 56 years of decay only 0. 40 g of a sample remains. what was the mass of the original

Svetradugi [14.3K]

Half-life is the time taken for the concentration of the substance to reduce by 50%. The original sample of strontium had a mass of 1.6 gms. Thus, option d is correct.

The half-life of any radioactive substance is the time period at which the concentration will get reduced to half the initial amount. The initial mass of Sr-90 is calculated as,

$N(t) = N_{0} (\dfrac{1}{2})^{ \frac{t }{t 1/2}}$

Given,

Quantity of the remaining substance N (t) = 0.40 gm

Initial radioactive substance quantity $N_{0}$ =?

Time duration (t) = 56 years

Half-life = 28 years

Substituting values above:

$\begin{aligned} 0.40 &= N_{0} (\dfrac{1}{2}) ^{{\frac{56}{28}}\\\\0.40 &= N_{0} (\dfrac{1}{2})^{2}\end{aligned}$

= 1.6 gm

Therefore, option d. the initial mass of Sr is 1.6 gm.

Learn more about half-life here:

brainly.com/question/16145921

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7 0

2 years ago

How does the atmosphere help to make Earth livable? Check all that apply.

Likurg_2 [28]

Answer:

- contains oxygen

- provides warmth

- blocks harmful energy from the Sun

Explanation:

The atmosphere is crucial when it comes to providing living conditions on Earth. The gases in the atmosphere manage to balance the things just about right, so that the life can thrive. The atmosphere has oxygen, the gas that is used by pretty much every organism to be able to function. With its greenhouse gases, the atmosphere manages to trap the heat inside, thus providing warmth to the Earth. The numerous layers of the atmosphere manage to block in big portion the harmful energy from the Sun, with a special accent on the ozone layer, a layer that manages to stop most of the UV radiation.

5 0

3 years ago

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