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3 years ago

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Describing physical and chemical changes:

1 answer:

svetoff [14.1K]3 years ago

8 0

Physical: The chemist could try to bend it to find out how malleable it is. He could also try to pull it into wires to find out how ductile it is.

Chemical: The chemist could put the metal into contact with other substances to get an idea of how reactive it is, and he could try to burn it and find out how flammable it is.

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If a mountain climber performs 180,000) of work climbing a 200 m cliff, how much force did he use?

ELEN [110]

Answer:

the question is not clear

Explanation:

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3 years ago

5000kg of ammonium nitrate per square kilometer of cornfield per year. how much nitric acid would be needed to make the fertiliz

Serggg [28]

$NH_3+HNO_3-> NH_4NO_3$

1 mole of nitric acid produce 1 mole of ammonium nitrate.

moles in 5000 kg of ammonium nitrate :

$n=\dfrac{5000\times 1000}{80}\\\\n=62500\ moles$ ( molecular mass of ammonium nitrate is 80 gm/mol )

So, number of moles of nitric acid required are also 62500 moles.

Mass of 62500 moles of nitric acid :

$mass = 62500\times 63 \\\\mass = 3937500\ gram\\\\mass = 393.75\ kg$

Hence, this is the required solution.

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3 years ago

A histidine is involved in an interaction with a glutamic acid that stabilizes the charged form of the histidine, such that the

Greeley [361]

Answer:

pKa of the histidine = 9.67

Explanation:

The relation between standard Gibbs energy and equilibrium constant is shown below as:

$\Delta{G^0} =-RT \ln \frac{[His]}{[His+]}$

R is Gas constant having value = 0.008314 kJ / K mol

Given temperature, T = 293 K

Given, $\Delta{G^0}=15\ kJ/mol$

So, Applying in the equation as:-

$15\ kJ/mol=-0.008314\ kJ/Kmol\times 293\ K\times \ln \frac{[His]}{[His+]}$

Thus,

$15\ kJ/mol=-0.008314\ kJ/Kmol\times 293\ K\times \ln \frac{[His]}{[His+]}$

$\frac{[His]}{[His+]}=e^{\frac{15}{-0.008314\times 293}$

$\frac{[His]}{[His+]}=0.00211$

Also, considering:-

$pH=pKa+log\frac{[His]}{[His+]}$

Given that:- pH = 7.0

So, $7.0=pKa+log0.00211$

<u>pKa of the histidine = 9.67</u>

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3 years ago

Draw structures for all constitutional isomers with the molecular

Andre45 [30]

The answer is B
APEX

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3 years ago

How many liters are in 62.9 g NaOH?

Sunny_sXe [5.5K]

Answer:

39.99711 grams.

Explanation:

Moles to Grams Naoh

1 mole is equal to 1 moles NaOH, or 39.99711 grams.

5 0

3 years ago