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3 years ago

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in an experiment magnesium ribbon was heated in air the product formed was found heavier than original ribbon.potassium manganat

e(vii)was heated im air and product formed was found lighter.explain different observations made

1 answer:

AlladinOne [14]3 years ago

5 0

Answer:

1: due to difference in reactivity and melting point

2 during the reaction both combine with oxygen in this case magnesium remain solid but some potassium vaporise

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A gas has a volume of 3.25 liters at 54 C and 231 kPa of pressure. At what temperature will the same gas take up 4.35 liters of

Firdavs [7]

Answer: 318 K

Explanation:

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1$ = initial pressure of gas = 231 kPa

$P_2$ = final pressure of gas = 168 kPa

$V_1$ = initial volume of gas = 3.25 L

$V_2$ = final volume of gas = 4.35 L

$T_1$ = initial temperature of gas = $54^oC=273+54=327K$

$T_2$ = final temperature of gas = ?

Now put all the given values in the above equation, we get:

$\frac{231\times 3.25}{327}=\frac{168\times 4.35}{T_2}$

$T_2=318K$

At 318 K of temperature will the same gas take up 4.35 liters of space and have a pressure of 168 kPa

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4 years ago

How does heat, without causing melting, damage a rock below eath’s surface

zheka24 [161]

It could be erosion

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3 years ago

Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according to the chemical equation shown below.

UNO [17]

<u>Answer:</u> The enthalpy change of the reaction is -361.6 kJ

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of sodium = 0.025 moles

Molar mass of sodium = 23 g/mol

Putting values in above equation, we get:

$0.025mol=\frac{\text{Mass of sodium}}{23g/mol}\\\\\text{Mass of sodium}=(0.025mol\times 23g/mol)=0.575g$

We are given:

Mass of water = 100.00 g

Mass of sodium = 0.575 g

Mass of solution = 100.00 + 0.575 = 100.575 g

To calculate the amount of heat absorbed, we use the equation:

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

where,

q = amount of heat absorbed = ?

m = mass of solution = 100.575 g

C = specific heat capacity of solution = 4.18 J/g°C

$\Delta T$ = change in temperature = $(T_2-T_1)=(35.75-25.00)=10.75^oC$

Putting all the values in above equation, we get:

$q=100.575g\times 4.18J/g^oC\times 10.75^oC=4519.34J=4.52kJ$

When heat is absorbed by the solution, this means that heat is getting released by the reaction.

<u>Sign convention of heat:</u>

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

For the given chemical reaction:

$2Na(s)+2H_2O(l)\rightarrow NaOH(aq.)+H_2(g)$

When 0.025 moles of sodium is reacted, the heat released by the reaction is 4.52 kJ

So, when 2 moles of sodium will react, the heat released by the reaction will be = $\frac{4.52}{0.025}\times 2=361.6kJ$

Hence, the enthalpy change of the reaction is -361.6 kJ

6 0

3 years ago

What term is used for the chemical composition of a compound

postnew [5]

Relative molecular mass or RMM is the answer.

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3 years ago

A fixed mass of gas has a volume of 92 cm cube and 3 degrees Celsius. What will be its volume at 18 degrees celsius if the press

8090 [49]

Answer:

94.8454

Explanation:

Let volume be V

Let Temperature be T

V1= 92

T1= 3C but to kelvin 273+3= 300K

V2= ?

T2= 18 C but to kelvin 18+273= 291

$\frac{v1}{t1} = \frac{v2}{t2}$

$\frac{92}{300} = \frac{v2}{291}$

$v2 \times 300 = 92 \times 291$

$v2 = \frac{92 \times 291}{300}$

$v2 = 94.8454$

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3 years ago