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mel-nik [20]
3 years ago
8

Ethanol is added to gasoline because the oxygen it contains improves gasoline's burning efficiency. Its combustion reaction is g

iven below. CH3CH2OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g) ∆H = - 1236 kJ a) Is this an exothermic or endothermic reaction? _______________ b) If 15.3 grams of pure ethanol is completely converted to products, calculate how much heat is absorbed or released, in: (1) kJ and in (2) kcal c) If 42.7 g of water vapor is produced, how much heat, in kJ, is absorbed or released?
Chemistry
1 answer:
ruslelena [56]3 years ago
7 0

Answer:

A) The reaction is exothermic reaction

B) 46 gm CH3CH2OH  = 1236KJ

15.3 gm ch3ch2OH = 1236/46 x 15.3

= 411.10 KJ..........released

therefore  1 KJ = 0.239 K cal

so, 411.10 x 0.239 kcal

= 98.2529 .................. released

c) 54 gm of H2O produced = 1236KJ

so, 42.7 gm H2O produced = 1236/54 x 42.7KJ

= 977.35 KJ released.

Explanation:

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Since atoms have more than one electron (other than atomic hydrogen) how do you account for the electrons remaining associated w
WARRIOR [948]
Answer: the electrons remain around the atomic nuclei due to the existence of a positive charge on the nuclei that, of course, atract the negative charged electrons. The protons are the paricles in the nuclei that hold the positive charge.

Justification:

First, I wish to explaing the sense of the question. The question arises because given that the electrons have negative electric charge how is that they do not repeal each other to the point that they end leaving the nucleous of the atom alone.

This is you know that equal charges repel each other, so how is it that the electrons stand around the nucleous instead of separateing and levaing the atomic nucleous alone.

The answer is due to the existence of a positive charge on the nuclei that, of course, atract the negative charged electrons. That positive charge is the protons.

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8 0
3 years ago
For the reaction represented by the equation cl2 + 2kbr ® 2kcl + br2, calculate the percentage yield if 200. g of chlorine react
alexgriva [62]
The  %  yield if 200g   of chlorine  react  with  excess Potassium bromide to  produce  410g of  bromine  is calculated as below

%  yield =  actual  yield/theoretical yield  x100
the  actual yield = 410 grams

calculate the  theoretical yield
by first  calculate the moles of chlorine used

mole=  mass/molar  mass
molar  mass of Cl2 =  35.5 x2= 71 g/mol

moles=  200g/71g/mol  = 2.82  moles

cl2 +2 KBr = 2KCl  +Br2

by use  of mole ratio between Cl2  to Br2  which is 1:1  the  moles of  Br2 is also = 2.82  moles

theoretical  mass =  moles x molar mass
molar mass of Br2= 79.9 x2= 159.8 g/mol

moles= 2.82g x 159.8 g/mol = 450.64 grams

% yield is therefore = 410g/450.64 x100 = 90.98 %


5 0
3 years ago
How many mg of metallic ions are in 1.0 mL of 0.10 M LINO3
Anton [14]

Answer:

0.6941 mg

Explanation:

First we <u>calculate how many LiNO₃ moles there are</u>, using the <em>given concentration and volume</em>:

  • 1.0 mL * 0.10 M = 0.10 mmol LiNO₃

As 1 mol of LiNO₃ contains 1 mol of Li,<em> in the problem solution there are 0.10 mmol of Li</em> (the only metallic ion present).

Now we<u> convert Li milimoles into miligrams</u>, using its <em>atomic mass</em>:

  • 0.10 mmol Li * 6.941 mg/mmol = 0.6941 mg

8 0
3 years ago
2.In a titration, 25.00 cm3 of a solution of hydrochloric acid reacted with 18.40 cm3 of sodium hydroxide solution of concentrat
telo118 [61]

Answer:

0.11mol/dm³

Explanation:

The reaction expression is given as:

             HCl   +  NaOH  →  NaCl + H₂O

Volume of acid  = 25cm³  = 0.025dm³

Volume of base  = 18.4cm³ = 0.0184dm³

Concentration of base  = 0.15mol/dm³

Solution:

The concentration of hydrochloric acid = ?

 To solve this problem, let us first find the number of moles of the base;

 Number of moles  = concentration x volume

 Number of moles  = 0.15mol/dm³ x 0.0184dm³  = 0.00276mol

From the balanced reaction equation;

          1 mole of NaOH will combine with 1 mole of HCl

Therefore,  0.00276mol of the base will combine with  0.00276mol of HCl

 So;

  Concentration of acid  = \frac{number of moles }{volume}   = \frac{ 0.00276}{0.025}   = 0.11mol/dm³

4 0
3 years ago
And earthquake create a type of way that shakes the ground if a large earthquake occurs in Greece how can the waves be felt acro
Likurg_2 [28]
Earthquakes release seismic waves which can move along a sea.
3 0
4 years ago
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