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3 years ago

I need help fast!!! Fill in the coefficients

Chemistry

1 answer:

Arturiano [62]3 years ago

6 0

Answer:

2HCl - H2 + Cl2

Explanation:

The two hydrochloric acid molecules decompose into one hydrogen molecule (H2) and one chlorine molecule (Cl2). If there is only one type of a specific molecule present, you should not have to add a coefficient of 1 behind it.

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What's the valency of lead in pbO2

Andru [333]

The valence of lead is 4.

Hence the name of the compound is called Lead (IV) oxide.

<h3>Further explanation</h3>

Given

PbO₂ compound

Required

The valence of Pb

Solution

The oxidation number of element O in the compound = -2, except for OF₂ the oxidation state = + 2 and the peroxides (Na₂O₂, BaO₂) the oxidation state = -1 and superoxide, for example KO₂ = -1/2.

The oxidation state in the uncharged compound = 0,

So The oxidation state of Pb :

Pb + 2.(-2) = 0

Pb - 4 = 0

Pb = +4

8 0

3 years ago

How can you separate mixture of suphur, nacl and nh4cl

weqwewe [10]

Answer:

Ammonium chloride, iron ,Sulphur and salt mixed together... they can be separated in the following methods.

1. Ammonium chloride is separated by sublimination... NC4CI is sublimable. Heat the mixture in a china dish and collect the funds of NC4CI (sublimable substance)

2. Bring a magnet close to the remaining mixture. Iron is magnetic substance and thus, it will be attracted towards the magnet. Iron is separated.

3. Sulphur is insoluble in water and salt is soluble. Add water to the remaining mixture and then wait for sedimentation. Separate the sulphur by decantation.

4. Heat the filtered salt solution to obtain salt.

3 0

3 years ago

commercial cold packs consist of solid NH4NO3 and water. In a coffee-cup calorimeter, 5.60g NH4NO3 is dissolved in 100g of water

fgiga [73]

Answer:

-1.37 kJ/mol

Explanation:

The expression for the calculation of the enthalpy of dissolution of [tex[NH_4NO_3[/tex] is shown below as:-

$\Delta H=m\times C\times \Delta T$

Where,

$\Delta H$ is the enthalpy of dissolution of [tex[NH_4NO_3[/tex]

m is the mass

C is the specific heat capacity

$\Delta T$ is the temperature change

Thus, given that:-

Mass of ammonium nitrate = 5.60 g

Specific heat = 4.18 J/g°C

$\Delta T=17.9-22.0\ ^0C=-4.1\ ^0C$

So,

$\Delta H=-1.25\times 4.18\times 3.9\ J=-95.9728\ J$

Negative sign signifies loss of heat.

Also, 1 J = 0.001 kJ

So,

$\Delta H=-0.096\ kJ$

Also,

Molar mass of [tex[NH_4NO_3[/tex] = 80.043 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{5.60\ g}{80.043 \ g/mol}$

$Moles= 0.06996\ mol$

Thus, $\Delta H=-\frac{0.096}{0.06996}\ kJ/mol=-1.37\ kJ/mol$

6 0

4 years ago

Pls help i am in 8th grade k12

zheka24 [161]

It’s definitely persuade!

4 0

2 years ago

the radius of the Sun is approximately 696,000 kilometers, while bacterial cells are as small as 1.9 × 10-4 millimeters. Express

Mazyrski [523]

Explanation;

Writing scientific notation :

Move the decimal to the left side until single digit of number remains before the decimal.
Then we will count the number of times we moved the decimal. Write this number as the exponential power of number '10'.
For Example: $2894.55=2.89455\times 10^{3}$

Radius of the sun = 696,000.0 kilometer

$1 km=10^3 m$

Radius of the sun can also be written as = $6.96\times 10^{5} km=6.96\times 10^{5}\times 10^3 m=6.96\times 10^{8} meter$

Size of bacterial cell = $1.9\times 10^{-4}$ millimeter

$1 mm=1\times 10^{-3} m$

Size of bacterial cell can also be written as = $1.9\times 10^{-4}\times 10^{-3} m=1.9\times 10^{-7} meter$

4 0

3 years ago