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4 years ago

PLEASE PLEASE PLEASE ANSWER THIS CORRECTLY ASAP 50 POINTS

Chemistry

1 answer:

tresset_1 [31]4 years ago

4 0

If I remember correctly, it would be B. A very large amount of energy is produced from a tremendous mass.

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If the hydrogen ion concentration is 10-7M, what is the pH of the solution? Show all work.

Kobotan [32]

Remember pH=-log(H ions). So it would be pH=-log(10^-7).

6 0

4 years ago

What is the difference between pure and applied chemistry?

bekas [8.4K]

Answer:

Explanation:

The major difference between pure and applied chemistry is the purpose and intent of the study.

Pure chemistry deals with the study of matter, matter transformations, and interactions between the different materials of the world, for only the sake of gaining empirical knowledge about the various substances that exist in the world. It does not really seek to apply this knowledge to do anything industrial.

Applied chemistry is the study of chemistry with the aim of utilizing this knowledge to solve the various problems that man faces. This approach of study is not for knowledge sake alone, rather it is for industrial application

3 0

3 years ago

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

UNO [17]

Answer: The enthalpy change of the reaction is -361.6 kJ

Explanation:

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.

Sign convention of heat:

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 volume will 0.875 moles of Kr occupy at STP

umka21 [38]

V = nRT/P = (0.875)(0.082057)(273)/(1) = 19.6 L

6 0

3 years ago

Given the reaction _K(s) +_ Cl2(g) → _KCl(s) what is the amount of K, in grams, needed to completely react with 2 moles of Cl2(g

damaskus [11]

Answer:

156.4g K

Explanation:

I'm not sure if it is correct but I think it should be this

What do we know so far?: 2K + 1Cl2 -> 2KCl, 2 mol of Cl2

What are we looking for?: #g of K

What is the ratio of K to Cl2?: 2:1

Set up equation: 2molCl2 x $\frac{2mol K}{1 mol Cl2}$

Cancel unwanted units: 2 x $\frac{2mol K}{1}$

Answer we got: 2 x 2mol K = 4mol K

Converting moles to grams: 4 x 39.1 (molar mass of K) = 156.4g K

3 0

3 years ago