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3 years ago

Why does potassium explode when exposed to water?

Chemistry

1 answer:

soldi70 [24.7K]3 years ago

4 0

Answer:

The highly unstable pure sodium or potassium wants to lose an electron and this splits the water atom, producing a negatively charged hydroxide ion and hydrogen and forming an explosive gas that ignites.

Explanation:

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What does the symbol (–Delta.Hfus) indicate in a phase change?

Rufina [12.5K]

Answer:

changes from a solid to a liquid

Explanation:

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3 years ago

A _____ is an experimental set-up that can be used to measure the heat of a chemical reaction or a physical change and determine

Eduardwww [97]

Answer:Calorimetry

Explanation: In this case, an instrument called Calorimeter is used to measure the amount of heat being transferred

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3 years ago

List the following elements in order , from best to worst conductor of electric current : silicon , copper, iodine.

Bingel [31]

Answer:

Iodine, Silicon, Copper.

Explanation:

Iodine is an insulator, which doesn't conduct electricity. Silicon is a semiconductor. Copper is a conductor.

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3 years ago

Calculate ΔHrxn for the following reaction: Fe2O3(s)+3CO(g)→2Fe(s)+3CO2(g) Use the following reactions and given ΔH′s. 2Fe(s)+3/

sesenic [268]

Answer:

The answer to your question is: ΔHrxm = -23.9 kJ

Explanation:

Data:

2Fe(s)+3/2O2(g)→Fe2O3(s), ΔH = -824.2 kJ (1)

CO(g)+1/2O2(g)→CO2(g) ΔH = -282.7 kJ (2)

Reaction:

Fe2O3(s)+3CO(g)→2Fe(s)+3CO2(g)

We invert (1) and change the sign of ΔH

Fe2O3(s) → 2Fe(s)+3/2O2(g) ΔH = 824.2 kJ

We multiply (2) by 3

3( CO(g)+1/2O2(g)→CO2(g) ΔH = -282.7 kJ) (2)

3CO(g)+3/2O2(g)→3CO2(g) ΔH = -848.1 kJ

We add (1) and (2)

Fe2O3(s) → 2Fe(s)+3/2O2(g) ΔH = 824.2 kJ

3CO(g)+3/2O2(g)→3CO2(g) ΔH = -848.1 kJ

Fe2O3(s) + 3CO(g)+3/2O2(g) → 2Fe(s)+3/2O2 + 3CO2(g)

Simplify

Fe2O3(s)+3CO(g)→2Fe(s)+3CO2(g) and ΔHrxm = -23.9 kJ

6 0

3 years ago

A chemist dissolves 248mg of pure hydrochloric acid in enough water to make up 140mL of solution.Calculate the pH of the solutio

evablogger [386]

Answer : The pH of the solution is, 1.31

Explanation : Given,

Mass of $HCl$ = 248 mg = 0.248 g (1 mg = 0.001 g)

Volume of solution = 140 mL

Molar mass of $HCl$ = 36.5 g/mole

First we have to calculate the concentration of hydrochloric acid.

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

$\text{Molarity}=\frac{\text{Mass of }HCl\times 1000}{\text{Molar mass of }HCl\times \text{Volume of solution (in mL)}}$

Now put all the given values in this formula, we get:

$\text{Molarity}=\frac{0.248g\times 1000}{36.5g/mole\times 140mL}=0.0485mole/L=0.0485M$

The concentration of HCl is, 0.0485 M

As we know that, HCl dissociates to give hydrogen ion and chloride ion.

The dissociation reaction is:

$HCl\rightarrow H^++Cl^-$

Concentration of HCl = Concentration of H⁺ = Concentration of Cl⁻ = 0.0485 M

Now we have to calculate the pH of the solution.

pH : It is defined as the negative logarithm of hydrogen ion concentration.

Mathematically,

$pH=-\log [H^+]$

$pH=-\log (0.0485)$

$pH=1.31$

Therefore, the pH of the solution is, 1.31

6 0

3 years ago