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2 years ago

If an endothermic process absorbs 256j how many kilocalories are absorbed

2 answers:

8 0

There are several units for expressing energy, Most common are joules and kilocalories.

The conversion factor of joule to kilocalories is
1 kilo calorie = 4184 J
∴ x kilo calorie = 256 J

x = $\frac{256}{4184} = 0.0611$ kilo calories

Thus, 256 J = 0.0611 kilocalories

astra-53 [7]2 years ago

5 0

Answer: 0.0612 kcalories

Explanation:

Endothermic processes are those processes in which heat is absorbed and exothermic processes are those processes in which heat is released.

Standard units for heat measurement are Joules and calories wherein

1 joule = 0.239 calorie.

As 1 Joule is equivalent to 0.239 calorie

256 Joules are equivalent to= $\frac{0.239}{1}\times 256=61.2calories$

Now 1 cal = 0.001 kcalories

Therefore 61.2 calories= $\frac{0.001}{1}\times 61.2=0.0612kcal$

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1. write the complete chemical symbol for the ion with 14 protons 15 neutrons and 18 electrons

motikmotik

Answer:

1. $Si^{-4}$

2. $Co^{+2}$

Explanation:

An ion is formed when an atom that is said to be neutral gains or losses electrons.

It is thought that a negative ion (anion) is produced as it gains electrons and a positive ion (cation) is formed when it loses an electron.

Atomic number is the total number of protons and electrons in a neutral atom.

From the information

Protons = 14

electron = 18

Net Charge = no of proton - no of electron

= 14 - 18 = -4

Mass number = 14 + 15 = 29

Thus, the chemical symbol = $Si^{-4}$

For ion with 27 proton, 32 neutrons and 25 electrons

Net charge = 27 - 25 = +2

Mass number = 27 + 32 = 59

Thus, the chemical symbol = $Co^{+2}$

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2 years ago

Briefly describe four ways that a beam can be strengthened?

lara31 [8.8K]

Answer:

1. Changing Beam Material

2. Corrugation

3. Changing Beam form

4. Steel Reinforcing Bars

Explanation:

Changing Beam Material

Some materials are stronger when used in beams than others. Beams made of steel for instance are stronger than beams made of wood. Therefore changing material can improve the strength of the beam. It is quite important to take into account the weights of the material though as different structures have different requirements.

Corrugation.

You can fold the beam into triangular shapes to increase strength. If you look at roofs you will notice that they are folded and this increased their strength. The same logic can be applied to beams.

Changing Beam Form

Another way to make Beams stronger is to change their form or rather their shape. Straight beams are not as strong as I-beams for instance. I-beams look like the capital letter I with the lines at both ends. I-beams are usually used in construction which shows that they are quite strong.

Steel Reinforcing Bars

When placed in concrete beams, Steel Reinforcing Bars which are also called Rebar can help strengthen a beam by helping it withstand the forces of tension. A concrete beam with Rebar inside it is known as Reinforced Concrete.

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3 years ago

7. NH2CO2NH4(s) when heated to 450 K undergoes the following reaction to produce a system which reaches equilibrium: NH2CO2NH4(s

Taya2010 [7]

Answer:

Value of equilibrium constant is 0.0888

Explanation:

Both $NH_{3}$ and $CO_{2}$ are gaseous. Hence equilibrium constant depends upon partial pressures of $NH_{3}$ and $CO_{2}$ .

Initially no $NH_{3}$ and $CO_{2}$ were present.

Hence mole fraction of $NH_{3}$ and $CO_{2}$ at equilibrium can be calculated from coefficient of $NH_{3}$ and $CO_{2}$ in balanced equation.

Mole fraction of $NH_{3}$ = (number of moles of $NH_{3}$ )/(total number of moles of $NH_{3}$ and $CO_{2}$ ) = $\frac{2moles}{(2+1)moles}=\frac{2}{3}$

Mole fraction of $CO_{2}$ = (number of moles of $CO_{2}$ )/(total number of moles of $NH_{3}$ and $CO_{2}$ ) = $\frac{1moles}{(2+1)moles}=\frac{1}{3}$