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Elis [28]
3 years ago
12

Give the reason why the empty crucible should be heated before starting the experiment

Chemistry
1 answer:
sdas [7]3 years ago
3 0
To make sure no cracks are in the crucible and also to remove any moisture present in the crucible by the process of heating.
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Which Statements below are true?
yKpoI14uk [10]

A. If motion starts and stops at the same location, then the displacment is zero.

D. Distance is always greater than or equal to the magnitutde of the displacement.

7 0
3 years ago
What are some ways we can monitor earthquakes ?
a_sh-v [17]

Answer:

Earthquakes are measured using instruments called seismometers, that detect the vibrations caused by seismic waves as they travel through the crust. Also, laser beams can be used

Explanation:

5 0
3 years ago
The following thermochemical equation is for the reaction of sodium(s) with water(l) to form sodium hydroxide(aq) and hydrogen(g
ra1l [238]

Answer:

1) When 6.97 grams of sodium(s) react with excess water(l), 56.0 kJ of energy are evolved.

2) When 10.4 grams of carbon monoxide(g) react with excess water(l), 1.04 kJ of energy are absorbed.

Explanation:

1) The following thermochemical equation is for the reaction of sodium(s) with water(l) to form sodium hydroxide(aq) and hydrogen(g).

2 Na(s) + 2H₂O(l) ⇒ 2NaOH(aq) + H₂(g) ΔH = -369 kJ

The enthalpy of the reaction is negative, which means that 369 kJ of energy are evolved per 2 moles of sodium. The energy evolved for 6.97 g of Na (molar mass 22.98 g/mol) is:

6.97g.\frac{1mol}{22.98g} .\frac{-369kJ}{2mol} =-56.0kJ

2) The following thermochemical equation is for the reaction of carbon monoxide(g) with water(l) to form carbon dioxide(g) and hydrogen(g).

CO(g) + H₂O(l) ⇒ CO₂(g) + H₂(g)  ΔH = 2.80 kJ

The enthalpy of the reaction is positive, which means that 2.80 kJ of energy are absorbed per mole of carbon monoxide. The energy evolved for 10.4 g of CO (molar mass 28.01 g/mol) is:

10.4g.\frac{1mol}{28.01g} .\frac{2.80kJ}{mol} =1.04kJ

3 0
4 years ago
A sample of iron with a mass of 200g releases 9840 cal when it freezes at it’s freezing point. What is the molar heat of fusion
antoniya [11.8K]

Answer:-

2747.7 Cal mol -1

Explanation:-

Molar heat of Fusion is defined as the amount of heat necessary to melt (or freeze) 1 mole of a substance at its melting point.

Atomic mass of Iron = 55.845 g mol-1

Mass of Iron = 200 g

Number of moles of Iron = 200 g / (55.845 g mol-)

= 3.581 moles

Heat released = 9840 Cal

Molar heat of Fusion = Heat released / Number of moles

= 9840 Cal / 3.581 moles

= 2747.7 Cal mol -1

8 0
3 years ago
Read 2 more answers
Two 4-grams paper towels are identical except for their thermal energies. Which paper towel has a higher temperature.
anygoal [31]

Answer:

a- The paper towel with more thermal energy

Explanation:

The paper towel with a higher temperature is one with more thermal energy.

Temperature is the degree of hotness or coldness of a body. And it is a measure of the average kinetic energy of the particles within a medium or body.

As body gains more thermal energy which is a form of kinetic energy, the average kinetic energy of its particles increases.

This will in turn lead to an increase in the temperature of the substance.

So, the paper towel with more thermal energy will have a higher temperature.

5 0
3 years ago
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