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3 years ago

Select the correct answer. Which substance is made of polymers? A. marble B. protein C. salt D. steel

Chemistry

2 answers:

Margaret [11]3 years ago

8 0

Answer:

B. protein

Explanation:

A polymer is defined as a molecule which has 'n' number of monomer units.

Similarly proteins are also polymers as they are made up of amino acids and contain a number of repeated units just like polymers.

Greeley [361]3 years ago

4 0

Answer:

the answer is B proteins

Explanation:

brainliest pls

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Solid iron (III) oxide reacts with hydrogen gas to form iron and water. How many grams of iron are produced when 440.23 grams of

Nookie1986 [14]

When 440.23 grams of iron(III) oxide are reacted with hydrogen gas, the amount of iron produced will be 307.66 grams

<h3>Stoichiometric calculation</h3>

From the equation of the reaction:

$Fe_2O_3 + 3H_2 --- > 2Fe + 3H_2O$

The mole ratio of iron(III) oxide to produced iron is 1:2.

Mole of 440.23 iron(III) oxide = 440.23/159.69 = 2.76 moles

Equivalent mole of produced iron = 2.76 x 2 = 5.52 moles

Mass of 5.52 moles of iron = 5.52 x 55.8 = 307.66 grams

More on stoichiometric calculations can be found here; brainly.com/question/27287858

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2 years ago

You pimp air into your volleyball the ball mass is?

Mumz [18]

Answer: When it comes to maintaining your volleyball ball, there are some things you should get accustomed to doing. One of the most important is knowing how to inflate it. The professionals keep the psi of a ball at 0.3 to 0.325 for indoor balls and at 0.175 to 0.225 for beach, or outdoor, balls.

Explanation:

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4 0

3 years ago

In Part III, the phenolphthalein indicator is used to monitor the equilibrium shifts of the ammonia/ammonium ion system. The phe

AnnZ [28]

The pink color in the solution fades. Some of the colored indicator ion converts to the colorless indicator molecule.

<h3>Explanation</h3>

What's the initial color of the solution?

$\text{NH}_4\text{Cl}$ is a salt soluble in water. $\text{NH}_4\text{Cl}$ dissociates into ions completely when dissolved.

$\text{NH}_4\text{Cl} \; (aq)\to {\text{NH}_4}^{+} \; (aq) +{\text{Cl}}^{-} \; (aq)$ .

The first test tube used to contain $\text{NH}_4\text{OH}$ . $\text{NH}_4\text{OH}$ is a weak base that dissociates partially in water.

$\text{NH}_4\text{OH} \; (aq) \rightleftharpoons {\text{NH}_4}^{+} \;(aq)+ {\text{OH}}^{-} \; (aq)$ .

There's also an equilibrium between $\text{OH}^{-}$ and ${\text{H}_3\text{O}}^{+}$ ions.

${\text{OH}}^{-}\;(aq) + {\text{H}_3\text{O}}^{+} \;(aq) \to 2\; \text{H}_2\text{O} \;(l)$ .

$\text{OH}^{-}$ ions from $\text{NH}_4\text{OH}$ will shift the equilibrium between $\text{OH}^{-}$ and ${\text{H}_3\text{O}}^{+}$ to the right and reduce the amount of ${\text{H}_3\text{O}}^{+}$ in the solution.

The indicator equilibrium will shift to the right to produce more ${\text{H}_3\text{O}}^{+}$ ions along with the colored indicator ions. The solution will show a pink color.

What's the color of the solution after adding NH₄Cl?

Adding $\text{NH}_4\text{Cl}$ will add to the concentration of ${\text{NH}_4}^{+}$ ions in the solution. Some of the ${\text{NH}_4}^{+}$ ions will combine with $\text{OH}^{-}$ ions to produce $\text{NH}_4\text{OH}$ .

The equilibrium between $\text{OH}^{-}$ and ${\text{H}_3\text{O}}^{+}$ ions will shift to the left to produce more of both ions.

${\text{OH}}^{-}\;(aq) + {\text{H}_3\text{O}}^{+} \;(aq) \to 2\; \text{H}_2\text{O} \;(l)$

The indicator equilibrium will shift to the left as the concentration of ${\text{H}_3\text{O}}^{+}$ increases. There will be less colored ions and more colorless molecules in the test tube. The pink color will fade.

7 0

4 years ago

Calcule la densidad del hidrógeno H2 en g/L a 327 mm Hg y 48ºc

tankabanditka [31]

<h3>The density of H₂ = 0.033 g/L</h3><h3>Further explanation</h3>

In general, the gas equation can be written

$\large {\boxed {\bold {PV = nRT}}}$

where

P = pressure, atm , N/m²

V = volume, liter

n = number of moles

R = gas constant = 0.082 l.atm / mol K (P= atm, v= liter),or 8,314 J/mol K (P=Pa or N/m², v= m³)

T = temperature, Kelvin

n = N / No

n = mole

No = Avogadro number (6.02.10²³)

n = m / MW

m = mass

MW = molecular weight

For density , can be formulated :

$\tt \rho=\dfrac{P\times MW}{R\times T}$

P = 327 mmHg = 0,430263 atm

R = 0.082 L.atm / mol K

T = 48 ºC = 321.15 K

MW of H₂ = 2.015 g/mol

The density :

$\rho=\dfrac{0,430263\times 2.015 }{0.082\times 321.15}\\\\\rho=0.033~g/L$

4 0

3 years ago

The solubility of a certain compound in ice-cold water is 0.16 g in 100 mL. Its solubility in hot water is 4.35 g in 100 mL. Wha

jonny [76]

Answer:

96.32 %

Explanation:

Given that:

The solubility of compound in hot water = 4.35 g / 100 mL

The solubility of compound in cold water = 0.16 g / 100 mL

Which means that in 100 mL of hot water, the dissolved compound is 4.35 g and in cold water, the dissolved compound is 0.16 g

Hence, on transition, compound that will catalyze is 4.35 - 0.16 g = 4.19 g

So,

$\%=\frac {4.19}{4.35}\times 100$

Percent recovery for re-crystallization of this compound from water= 96.32 %

3 0

3 years ago