How many atom will be present in2.7 g of aluminumal=22 na=6.02×^23

PbO2 + 4HCl --- PbCl2 + Cl2 + 2H2O who buys electrons and who loses electrons?

SIZIF [17.4K]

Answer: Electrons are taken up by $PbO_2$ and they are lost by $HCl$

Explanation:

Redox reaction is defined as the reaction in which oxidation and reduction take place simultaneously. It is also called the reaction where the exchange of electrons takes place.

An oxidation reaction is defined as the reaction in which a chemical species loses electrons takes place. In this reaction, the oxidation state of a substance gets increased.

A reduction reaction is defined as the reaction in which a chemical species gains electrons takes place. In this reaction, the oxidation state of a substance gets reduced.

For the given chemical reaction:

$PbO_2+4HCl\rightarrow PbCl_2+Cl_2+2H_2O$

The half-reactions for this redox rection follows:

Oxidation half-reaction: $2HCl\rightarrow ClO_2 + 2e^-$

Reduction half-reaction: $PbO_2+2e^-\rightarrow PbCl_2$

Hence, electrons are taken up by $PbO_2$ and they are lost by $HCl$

8 0

3 years ago

How many grams of lithium are in a 1320 [mAh] cell phone battery? Note that [mAh] is a unit of charge.

AURORKA [14]

Answer:

0.396 grams of lithium

Explanation:

Lithium-ion batteries have the main feature of using lithium salts as a "bridge" between the positive pole (anode) to the negative (cathode) to allow the passage of energy that will give life to our device. In the case of lithium polymer batteries, the difference is that the lithium salt is contained in a polymer, or gel, to keep it safe from spills.

In both cases, when the battery is discharging, lithium ions travel from the cathode to the anode through their "bridges" to supply the energy until all the ions are in the anode, it is at this time when the battery is out of stock The ions travel in the opposite direction during charging (from the anode to the cathode).

The calculation used to determine the amount of lithium that the lithium cell batteries have is as follows:

0.3 x amp hour capacity = g of lithium

where amp hour = Ah

In our case:

0.3 x 1.32 = 0.396 g of lithium

5 0

3 years ago

When hydrochloric acid is poured over potassium sulfide, 43.7 mLmL of hydrogen sulfide gas is produced at a pressure of 758 torr

kvasek [131]

Answer:

0.196 grams of K2S reacted

Explanation:

When hydrochloric acid is poured over potassium sulfide, 43.7 mLmL of hydrogen sulfide gas is produced at a pressure of 758 torrtorr and 26.0 ∘C

How much potassium sulfide has reacted in grams?

Step 1: Data given

Volume of hydrogen sulfide (H2S) produced = 43.7 mL

Pressure = 758 torr = 758/760 = 0.9973684 atm

Temperature = 26.0 °C = 273 + 26 = 299 K

Step 2: The balanced equation

2 HCl + K2S → H2S + 2 KCl

Step 3: Calculate moles H2S

p*V = nRT

n = (pV)/(RT)

⇒ with n= the number of moles of H2S

⇒ with p = the pressure = 0.9973684 atm

⇒ with V = the volume of the gas = 43.7 mL = 0.0437 L

⇒ with R = the gas constant = 0.08206 L*atm/K*mol

⇒ with T = The temperature = 26°C = 299 Kelvin

n = (0.9973684 * 0.0437)/ (0.08206*299)

n = 0.001776 moles H2S

Step 4: calculate moles of K2S

For 2 moles HCl we need 1 mol K2S to produce 1 mol H2S and 2 moles KCl

For 0.001776 moles H2S produced, we need 0.001776 moles K2S

Step 5: Calculate mass of K2S

Mass K2S = moles K2S * molar mass K2S

Mass K2S = 0.001776 moles * 110.26 g/mol

Mass K2S = 0.196 grams K2S

0.196 grams of K2S reacted

6 0

3 years ago

Stoichiometry is best defined as the

Oxana [17]

Stoichiometry is “quantitative relationship” among the “reactants” and the “products” in a “chemical reaction”.

Explanation:

In stoichiometry “stoicheion” means element and “metron” means measure in Greek. The stoichiometric calculation depends upon “stoichiometric coefficients” in a “chemical equation” which can be explained as the “number of moles” of each substance (reactants or products). Stoichiometric calculation is done as follows:

For example reaction between nitrogen and hydrogen to form ammonia as

$\mathrm{N}_{2}(\mathrm{g})+3 \mathrm{H}_{2}(\mathrm{g}) \longrightarrow 2 \mathrm{NH}_{3}(\mathrm{g})$

Here stoichiometric coefficients show that “one molecule of nitrogen” reacts with “three molecules of hydrogen” to form “two molecules of ammonia”. Multiplying Avogadro number $6.022 \times 10^{23}$ to no of molecules in equation: