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3 years ago

Explain the process of fossil creation.

1 answer:

6 0

When an animal or plant dies in a muddy environment, the soft tissue will start to decompose which leaves behind hard bones/shells. Over time the sediment will build over the top and it will harden into a rock still showing the bones.

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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

CH3-CHCl-CH2-CH2-CH2CHCl-CH3 +concentrated KCN

Phantasy [73]

Is this chemistry or something else?

8 0

4 years ago

Read 2 more answers

Given that a mass of a ball is (36.0 g), and the volume is (8.0 mL), what is the ball's density in g/mL?

max2010maxim [7]

Answer:

4.5g/mL

Explanation:

Given parameters:

Mass of ball = 36g

Volume of the ball = 8mL

Unknown:

Density of the ball = ?

Solution:

Density is the mass per unit volume of a substance.

Density = $\frac{mass}{volume}$

So;

Density = $\frac{36}{8}$ = 4.5g/mL

5 0

3 years ago

How many liters are contain 1.75 mol of f2 gas at stp?

Vanyuwa [196]

At STP condition 1 mol of any ideal gas will have a volume of 22.4L

1.75 mol of F2 x 22.4 L / 1 mol = 39.2 L

3 0

3 years ago

How many molecules of O2 are in 153.9 g O2?

MrRissso [65]

Answer:

2.895*10^24

Explanation:

mass of Oxygen give = 153.9g

molar mass of O2 molecule = 16*2=32g/mol

n= mole

To find the mole

n= mass/ molar mass

n= 153.9/32

n=4.81mol.

To find the number of molecules of o

Nm= number of molecule

Nn = Number of mole

NA = number of Avogados

Nm= Nn * NA

Nm= 4.81 *6.02*10^23

Nm= 2.895*10^24

3 0

3 years ago