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3 years ago

Is a instant cold pack Endothermic or Exothermic reaction? Explain.

Chemistry

1 answer:

marshall27 [118]3 years ago

3 0

Answer:

Yes an instant cold pack is a perfect example of an endothermic reaction.

Explanation:

They are endothermic because they absorb heat energy from their surroundings. This means that the surroundings of endothermic reactions are colder as a result of the reaction.For example melting ice is a type of this reaction

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How can atoms have more than 32 electons?

guajiro [1.7K]

86 atoms have more electrons than Germanium

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3 years ago

I have a 4 amino acid peptide of unknown sequence with a curious titration profile around pH = 6. If Iknow that the peptide N-te

netineya [11]

Answer:

c. Histidine

Explanation:

Histidine is a compound that is normally used for the generation of protein. Three amino acids commonly have basic side chain when the pH is neutral. The conjugate acid in histidine has a pKa of approximately 6. Based on the description of the experimental analysis provided in the statement, the right option is option c.

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3 years ago

Balance the following half reaction in basic conditions. Then, indicate the coefficients for H2O and OH– for the balanced half r

Ugo [173]

Answer:

The ballance half reactions are:

Mg²⁺ + 2e⁻ → Mg

6OH⁻ + Si → SiO₃²⁻ + 4e⁻ + 3 H₂O

Coefficients for H2O and OH– are 3 for H₂O (in products side) and 6 for OH⁻ (in reactants side)

Explanation:

Si (s) + Mg(OH)₂ (s) → Mg (s) + SiO₃²⁻ (aq)

Let's see the oxidations number.

As any element in ground state, we know that oxidation state is 0, so Si in reactants and Mg in products, have 0.

Mg in reactants, acts with +2, so the oxidation number has decreased.

This is the reduction, so it has gained electrons.

Si in reactants acts with 0 so in products we find it with +4. The oxidation number increased it, so this is oxidation. The element has lost electrons.

Let's take a look to half reactions:

Mg²⁺ + 2e⁻ → Mg

Si → SiO₃²⁻ + 4e⁻

In basic medium, we have to add water, as the same amount of oxygen we have, IN THE SAME SIDE. We have 3 oxygens in products, so we add 3 H₂O and in the opposite site we can add OH⁻, to balance the hydrogen. The half reaciton will be:

6OH⁻ + Si → SiO₃²⁻ + 4e⁻ + 3 H₂O

If we want to ballance the main reaction we have to multiply (x2) the half reaction of oxidation. So the electrons can be ballanced.

2Mg²⁺ + 4e⁻ → 2Mg

Now, that they are ballanced we can sum the half reactions:

2Mg²⁺ + 4e⁻ → 2Mg

6OH⁻ + Si → SiO₃²⁻ + 4e⁻ + 3 H₂O

2Mg²⁺ + 4e⁻ + 6OH⁻ + Si → 2Mg + SiO₃²⁻ + 4e⁻ + 3 H₂O

7 0

3 years ago

Difference between proton and electron

Vanyuwa [196]

Answer:

An electron is a negatively charged component of an atom

the proton is a positively charged body.

Explanation:

3 0

3 years ago

1. A given mass of air has a volume of 6.00 L at 80.0°C. At constant pressure, the temperature is

earnstyle [38]

3 L will be the final volume for the gas as per Charle's law.

Answer:

Explanation:

The kinetic theory of gases has two significant law which forms the backdrop of motion of gases. They are Charle's law and Boyle's law. As per Charle's law, the volume of any gas molecule at constant pressure is directly proportional to the temperature of the molecule.

V∝ T

Since, here two volumes are given and at two different temperatures with constant pressure. Then as per Charle's law, the relation between the volumes of air at different temperature will be

$\frac{V_{1} }{T_{1} }= \frac{V_{2} }{T_{2} }$

So in this case, V1 = 6 L and T1 = 80° C. Similarly, T2 = 40° C. So we have to determine the V2.

$\frac{6}{80}=\frac{V_{2} }{40}$

$V_{2}=\frac{6*40}{80}=3 L$

So, 3 L will be the final volume for the gas as per Charle's law.

4 0

3 years ago