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3 years ago

We can prove a theory to be correct by performing the right experiment. False or true

Chemistry

1 answer:

eimsori [14]3 years ago

4 0

Answer:

true

Explanation:

because if you find the right answer that proves the theory to be correct.

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When 1.045 g of CaO is added to 50.0 mL of water at 25.0 °C in a calorimeter, the temperature of the water increases to 32.3 °C.

Rus_ich [418]

Answer:

1.71 kJ/mol

Explanation:

The expression for the calculation of the enthalpy change of a process is shown below as:-

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

Where,

$\Delta H$ is the enthalpy change

m is the mass

C is the specific heat capacity

$\Delta T$ is the temperature change

Thus, given that:-

Mass of CaO = 1.045 g

Specific heat = 4.18 J/g°C

$\Delta T=32.3-25.0\ ^0C=7.3\ ^0C$

So,

$\Delta H=1.045\times 4.18\times 7.3\ J=31.88713\ J$

Also, 1 J = 0.001 kJ

So,

$\Delta H=0.03189\ kJ$

Also, Molar mass of CaO = 56.0774 g/mol

$Moles=\frac{Mass}{Molar\ mass}=\frac{1.045}{56.0774}\ mol=0.01863\ mol$

Thus, Enthalpy change in kJ/mol is:-

$\Delta H=\frac{0.03189}{0.01863}\ kJ/mol=1.71\ kJ/mol$

8 0

3 years ago

If i have 340mL of a 1.5 M NaBr solution, What will the concentration be for 1000mL?

Gekata [30.6K]

Answer:

0.51M

Explanation:

Given parameters:

Initial volume of NaBr = 340mL

Initial molarity = 1.5M

Final volume = 1000mL

Unknown:

Final molarity = ?

Solution;

This is a dilution problem whereas the concentration of a compound changes from one to another.

In this kind of problem, we must establish that the number of moles still remains the same.

number of moles initially before diluting = number of moles after dilution

Number of moles = Molarity x volume

Let us find the number of moles;

Number of moles = initial volume x initial molarity

Convert mL to dm³;

1000mL = 1dm³

340mL gives $\frac{340}{1000}$ = 0.34dm³

Number of moles = initial volume x initial molarity = 0.34 x 1.5 = 0.51moles

Now to find the new molarity/concentration;

Final molarity = $\frac{number of moles}{Volume}$ = $\frac{0.51}{1}$ = 0.51M

We can see a massive drop in molarity this is due to dilution of the initial concentration.

6 0

3 years ago

Identify the type of reaction in KBrO3(s)  KBr(s) + O2(g)

lord [1]

I believe an oxidation reaction is occurring

5 0

3 years ago

Read 2 more answers

Question # 4 & 5. help CHEMISTRY

laila [671]

1. A thermodynamic quantity that is the difference between the internal energy of a system and the product of itsabsolute temperature and entropy; the capacity of a system to do work, as in an exothermic chemical reaction.2. A thermodynamic quantity that is the difference between the enthalpy and the product of the absolute temperatureand entropy of a system. Also called Gibbs free energy.

4 0

3 years ago

Which requires more energy to move an electron?

Mandarinka [93]

Answer:

From n=1 to n=2

Explanation:

Electrons in n=1 are strongly attracted to the nucleus and therefore will require great force to overcome the electrostatic force of attraction to displace them from the energy level to another.

The electrostatic force reduces as you progress to the outer energy levels.

4 0

3 years ago

Read 2 more answers