All categories

3 years ago

Find the initial temperature of Aluminum if 35 g of it produces 781.2 Joules at the final temperature of 44.3 ºC.

Chemistry

1 answer:

Annette [7]3 years ago

6 0

Answer:

T initial = 19.55°C

Explanation:

Given data:

Mass of Al = 35 g

Energy produces = 781.2 J

Final temperature = 44.3°C

Initial temperature = ?

Solution:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Specific heat capacity of Al is 0.902 J/g.°C

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = Final temperature - initial temperature

Q = m.c. ΔT

781.2 J = 35 g×0.902 J/g.°C× (T final - T initial)

781.2 J = 35 g×0.902 J/g.°C× (44.3°C -T initial )

781.2 J = 31.57 j/°C× (44.3°C -T initial )

781.2 J/ 31.57 j/°C = (44.3°C -T initial )

24.75°C = (44.3°C -T initial )

24.75° - 44.3°C = -T initial

T initial = 19.55°C

You might be interested in

Please select the word from the list that best fits the definition

Alexandra [31]

I believe it is either A. or C. my guess is A.

7 0

2 years ago

To draw a Lewis structure for a

liq [111]

40 electrons

Explanation:

The N for silicon tetrachloride, SiCl₄ is 40 electrons. The needed electrons that would be used to complete the lewis structure of the compound is actually 40 electrons. This number of electron will help the compound attain a noble configuration.

The compound SiCl₄ is a covalent one. Here, there is sharing of electrons between two atoms.
In drawing the electron dot formula, one must take into account the Available electrons and the Needed electrons.
The Available electrons are sum of the valence electrons that can be accessed for the bonding. Si has 4 valence electrons, Cl has 7 valence electrons this makes a total of 4 + 7(4 atoms of chlorine), 32 available electrons.
But to make a complete octet like that of noble gases, each atom most have 8 complete outer most electrons. This is the needed number of electrons. Since there are 5 atoms i.e 4 atoms of chlorine and 1 atom of Silicon, the needed electrons will be 5x8 = 40 electrons.

Learn more:

lewis structure : brainly.com/question/6215269

#learnwithBrainly

8 0

3 years ago

In general, which of the following statements about electron-pair geometries is true?

Sergio [31]

Answer:

same

Explanation:

3 0

3 years ago

A sodium ion, Na+, with a charge of 1.6×10−19C and a chloride ion, Cl− , with charge of −1.6×10−19C, are separated by a distance

sasho [114]

Answer:

$W\geq 2.1x10^{-19}J$

Explanation:

Due to Coulomb´s law electric force can be described by the formula $F=K\frac{q_{1}.q_{2}}{r^{2}}$ , where K is the Coulomb´s constant ( $9x10^{9} N\frac{m^{2} }{C^{2} }$ ), $q_{1}$ = Charge 1 (Na+ in this case), $q_{2}$ is the charge 2 (Cl-) and r is the distance between both charges.

Work made by a force is W=F.d and total work produced is the change in energy between final and initial state. this is $W=W_{f} -W_{i}$ .

so we have $W=W_{f} -W_{i} =(K\frac{q_{(Na+)}q_{(Cl-)}rf}{r_{f} ^{2}})-(K\frac{q_{(Na+)}q_{(Cl-)}ri}{r_{i} ^{2}})=Kq_{(Na+)}q_{(Cl-)[\frac{1}{{r_{f}}} -\frac{1}{{r_{i}}}]$

Given that ri= 1.1nm= $1.1x10^{-9}m$ and rf= infinite distance

$W=(9x10^{9})(1.6x10^{-19})(-1.6x10^{-19})[\frac{1}{\alpha }-\frac{1}{(1.1x10^{-9})}]=2.1x10^{-19}J$

6 0

3 years ago

How many moles are in 35.0 grams of H₂O?

Nikitich [7]

1.94 moles

I did 35/18.02 because 18.02 is the molar mass of water

3 0

3 years ago