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Monica [59]
2 years ago
13

During what change is heat absorbed?

Chemistry
2 answers:
Alisiya [41]2 years ago
6 0
Endothermic reactions absorb heat and exotbermic releases heat
Ostrovityanka [42]2 years ago
3 0

Answer: <u>endothermic</u>

<u />

Explanation: <u>A chemical reaction or physical change is endothermic if heat is absorbed by the system from the surroundings. </u>

You might be interested in
Water only gets evaporated from the ocean. True or false?
krek1111 [17]

Answer:

false

Explanation:

7 0
3 years ago
combustion analysis of a hydrocarbon produced 33.01g CO2 and 13.51g H2O. Calculate the empirical formula for the hydrocarbon
masya89 [10]

Answer:

\rm CH_2.

Explanation:

Carbon and hydrogen are the only two elements in a hydrocarbon. When a hydrocarbon combusts completely in excess oxygen, the products would be \rm CO_2 and \rm H_2O. The \rm C and \rm H would come from the hydrocarbon, while the \rm O atoms would come from oxygen.

Look up the relative atomic mass of these three elements on a modern periodic table:

  • \rm C: 12.011.
  • \rm H: 1.008.
  • \rm O: \rm 15.999.

Calculate the molar mass of \rm CO_2 and \rm H_2O:

M(\mathrm{CO_2}) = 12.011 + 2 \times 15.999 = 44.009\; \rm g \cdot mol^{-1}.

M(\mathrm{H_2O}) = 2 \times 1.008 + 15.999 = 18.015\; \rm g \cdot mol^{-1}

Calculate the number of moles of \rm CO_2 molecules in 33.01\; \rm g of \rm CO_2\!:

\displaystyle n(\mathrm{CO_2}) = \frac{m(\mathrm{CO_2})}{M(\mathrm{CO2})} = \frac{33.01\; \rm g}{44.009\; \rm g\cdot mol^{-1}} \approx 0.7501\; \rm mol.

Similarly, calculate the number of moles of \rm H_2O molecules in 13.51\; \rm g of \rm H_2O\!:

\displaystyle n(\mathrm{H_2O}) = \frac{m(\mathrm{H_2O})}{M(\mathrm{H_2O})} = \frac{13.51\; \rm g}{18.015\; \rm g\cdot mol^{-1}} \approx 0.7499\; \rm mol.

Note that there is one carbon atom in every \rm CO_2 molecule. Approximately0.7501\; \rm mol of \rm CO_2\! molecules would correspond to the same number of \rm C atoms. That is: n(\mathrm{C}) \approx 0.7501\; \rm mol.

On the other hand, there are two hydrogen atoms in every \rm H_2O molecule. approximately 0.7499\; \rm mol of \rm H_2O molecules would correspond to twice as many \rm H\! atoms. That is: n(\mathrm{H}) \approx 2 \times 0.7499 \; \rm mol\approx 1.500\; \rm mol.

The ratio between the two is: n(\mathrm{C}): n(\mathrm{H}) \approx 1:2.

The empirical formula of a compound gives the smallest whole-number ratio between the elements. For this hydrocarbon, the empirical formula would be \rm CH_2.

6 0
3 years ago
iron will react with oxygen to produce Fe2O3. how many grams of Fe2O3 will he produced if 0.18 mil of Fe reacts?
nasty-shy [4]

Answer:

14.4g

Explanation:

First, we need to write a balanced equation for the reaction between Fe and O2 to produce Fe2O3. This is illustrated below:

4Fe + 3O2 —> 2Fe2O3

From the balanced equation,

4moles of Fe produced 2moles of Fe2O3.

Therefore, 0.18mol of Fe will produce = (0.18x2) /4 = 0.09mol of Fe2O3.

Now we need to find the mass present in 0.09mol of Fe2O3. This can be achieved by doing the following:

Molar Mass of Fe2O3 = (56x2) + (16x3) = 112 + 48 = 160g/mol

Number of mole of Fe2O3 = 0.09mol

Number of mole = Mass /Molar Mass

Mass = number of mole x molar Mass

Mass of Fe2O3 = 0.09 x 160 = 14.4g

6 0
3 years ago
Please help me on this I’ll give 30 points
Rufina [12.5K]

Answer:

                     1. 10.66 moles of Al

                     2.  2.5 moles of Al₂O₃

                     3. 143.87 g of SO₂

Explanation:

                    The balance chemical equation is as follow,

                                      4 Al + 3 O₂ → 2 Al₂O₃

<h3>1.</h3>

According to balance chemical equation,

                       3 moles of O₂ required  =  4 moles of Al

So,

                     8 moles of O₂ will require  =  X moles of Al

Solving for X,

                      X =  8 mol × 4 mol / 3 mol

                      X =  10.66 moles of Al

<h3>2.</h3>

According to balance chemical equation,

                       4 moles of Al produced  =  2 moles of Al₂O₃

So,

                     5 moles of Al will produce  =  X moles of Al₂O₃

Solving for X,

                      X =  5 mol × 2 mol / 4 mol

                      X =  2.5 moles of Al₂O₃

<h3>3.</h3>

The balance chemical equation for the oxidation of carbon disulfide is as follow;

                                CS₂ + 3 O₂ → CO₂ + 2 SO₂

Step 1: <u>Calculate Moles of CS₂ as;</u>

                  Moles  =  Mass / M.Mass

                  Moles  =  85.5 g / 76.14 g/mol

                  Moles  =  1.12 moles of CS₂

Step 2: <u>Find out moles of SO₂ as;</u>

According to balance chemical equation,

                       1 mole of CS₂ produced  =  2 moles of SO₂

So,

                     1.12 moles of CS₂ will produce  =  X moles of SO₂

Solving for X,

                      X =  1.12 mol × 2 mol / 1 mol

                      X =  2.24 moles of SO₂

Step 3: <u>Calculate Mass of SO₂ as;</u>

                  Mass  =  Moles × M.Mass

                  Mass  =  2.24 mol × 64.06 g/mol

                  Mass  =  143.87 g of SO₂

4 0
3 years ago
The energy source used in nuclear power plants today is
Klio2033 [76]

Answer:

B I have taken the quiz already 90%

7 0
3 years ago
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