1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ludmilkaskok [199]
4 years ago
12

In the reaction between formic acid (HCHO2) and sodium hydroxide, water and sodium formate (NaCHO2) are formed. To determine the

heat of reaction, 75.0 mL of 1.07 M HCHO2 was placed in a coffee cup calorimeter at a temperature of 21.9 °C, and 45.0 mL of 1.78 M NaOH, also at 21.9 °C, was added. The mixture was stirred quickly with a thermometer, and its temperature rose to 25.5 °C. Write the balanced chemical equation for the reaction. Calculate the heat of reaction in joules. Assume that the specific heats of all solutions are 4.18 J g-1°C-1 and that all densities are 1.00 g mL-1. What is the heat of reaction per mole of acid (in units of kJ mol-1).
Write the balanced reaction that takes place:
Heat of reaction = ________________---- kJ/mol
Chemistry
1 answer:
Gnom [1K]4 years ago
5 0

Answer:

Balanced equation: HCHO₂ + NaOH → NaCHO₂ + H₂O

Heat of reaction:  22.6 kJ/mol

Explanation:

The chemical equation is the sum of the reactants given the products:

HCHO₂ + NaOH → NaCHO₂ + H₂O

To balance the equation, the elements must be in the same amount in the reactants and the products. As we can see, there are the same amount of elements on each side, so the equation is balanced.

The heat flows can be calculated by:

Q = m*cp*ΔT

Where m is the mass of the substances (mass of formic acid + mass of sodium hydroxide), cp is the specif heat, and ΔT is the variation at temperature (final - initial).

Mass is the density multiplied by the volume, so:

m = 1*75 + 1*45 = 120 g

Q = 120*4.18*(25.5 - 21.9)

Q = 1,805.76 J = 1.81 kJ

The number of moles of the reactants can be calculated by the volume multipled by the concentration:

HCHO₂ = 0.075L * 1.07 mol/L = 0.08025 mol

NaOH = 0.045L * 1.78 mol/L = 0.0801 mol

So, NaOH is limiting (stoichiometry is 1:1, so it's necessary the same amount of the reactants), and the heat of the reaction will be calculated by it.

ΔH = Q/n

ΔH = 1.81/0.0801

ΔH = 22.6 kJ/mol

You might be interested in
An alkene X undergoes ozonolysis and gives two compounds Y and Z of molecular formula CaHO. Y and Z are functional isomers of ea
lys-0071 [83]

i. The given compound X is 2-methyl pent-2-ene. When it is reacted with ozone it forms an ozonide in the first step. In the second step the reduce to forms acetone and propanal.

ii. The structural formula of Y is CH_3-CO-CH_3 and Z is CH_3-CH_2-CHO.

iii. Alkenes, upon catalytic hydrogenation, form alkanes. This will occur in the presence of Nickel as the catalyst.

iv. The process of ozonolysis is useful in the field of pharmaceutics.

v. The test of unsaturation can be performed by passing a compound through Bromine water.

<h3>What is ozonolysis?</h3>

Ozonolysis is a reaction used in organic chemistry to determine the position of a carbon-carbon double bond in unsaturated compounds.

i. The given alkene X, that is subject to ozonolysis would be 2-methyl-2-pentene. Upon exposure to ozone, an ozonide is initially formed, after which it is broken down into 2 products - acetone and propanal, both with the molecular formula C₃H₆O.

The given compound X is 2-methyl pent-2-ene. When it is reacted with ozone it forms an ozonide in the first step. In the second step the reduce to forms acetone and propanal.

ii. The formulas of Y is CH_3-CO-CH_3 and Z is CH_3-CH_2-CHO. They are functional isomers as they have the same molecular formula but different functional groups - ketone and aldehyde.

iii. When alkenes undergo catalytic hydrogenation, they form alkanes, X will form 2 methyl petane on reaction with hydrogen gas in presence of Ni.

iv. The ozonolysis is used for the industrial-scale synthesis of pharmaceuticals.

v. The unsaturation of compound X can be proved by the bromine water test. As on reaction with it, the brown colour of bromine water becomes colourless due to the formation of dibromo alkane.

Learn more about the ozonolysis here:

brainly.com/question/14356308

#SPJ1

5 0
2 years ago
Silver is a metal; it reacts with oxygen which is a non-metal to form Silver Oxide. The bond between Silver and Oxygen is called
BabaBlast [244]
It is called an ionic bond
7 0
3 years ago
When 0.100 M NaOH is titrated with 25.00 mL 0.0500 M HBr, which of the following is correct for this titration?
alisha [4.7K]

Answer:

c) B, C

Explanation:

NaOH(aq) + HBr(aq) -----> NaBr(aq) +H2O(l)

1) concentration of acid CA= 0.05 M

Concentration of base CB= 0.1 M

Volume of acid VA= 25.00ml

Volume of base VB= unknown

Number of moles of acid NA= 1

Number of moles of base NB= 1

CAVA/CBVB = NA/NB

CAVANB =CBVBNA

VB= CAVANB/CB NB

VB= 0.05 × 25 × 1/ 0.1 ×1

VB= 12.5 ML

2.

8 0
4 years ago
What is the empirical formula of the compound that is 25.3% magnesium and 74.7% chlorine
Margarita [4]

Answer: MgCl_2

Explanation:

25.3% Mg

74.7% Cl

First step: change % to g

25.3g Mg

74.7g Cl

Second step: calculate g/mol of each compound. You can do this by using the atomic mass.

25.3gMg(\frac{1mol}{24.30g})=1.04mol

74.7gCl(\frac{1mol}{35.45g} )=2.11mol

Third step: determine the lowest number and divide everything by it. Of the result, extract whole number only.

Mg=\frac{1.04}{1.04} =1

Cl=\frac{2.11}{1.04}=2

Fourth step: Write each compound with their respective number below.

This empirical formula should be: MgCl_2

4 0
4 years ago
Write the equilibrium constant for this reaction in terms of the equilibrium constants, Ka and Kb, for reactions a and b below:
Mars2501 [29]

Answer:

(a) Ka = \frac{(SO3)^{2} }{(S)^{2}*(O2)^{3}  }

(b) Kb = \frac{(SO2)^{1} }{(S)^{1} *(O2)^{1} }

Explanation:

Correct equation: 2S(s) + 3O_{2}(g) ⇒ 2SO_{3}(g)\\

S(s) + O_{2}(g) ⇒ 2SO_{2}(g)\\

Equilibrium constant refers to a relation between products and reactants of an equilibrium reaction with respect to the components concentration and coefficients.

generally in an equilibrium reaction between reactant A, B, C and D shown below

aA+bB ⇒ cC + dD

the equilibrium constant is represented by

k = \frac{C^{c} *D^{d} }{A^{a} *B^{b} }

comparing this with the equation in the problem the equilibrium constants ka and kb are;

Ka = \frac{(SO3)^{2} }{(S)^{2}*(O2)^{3}  }

Kb = \frac{(SO2)^{1} }{(S)^{1} *(O2)^{1} }

7 0
3 years ago
Other questions:
  • ) how much of the primary standard benzoic acid (fm 122.12, density 1.27 g/ml) should you weigh out to obtain a 100.0 mm aqueous
    14·1 answer
  • A sample of well water is tested and found to have 1350 ppm Iron. If a 1000g sample was tested, how many grams of iron were in i
    5·1 answer
  • Is the element CH4 a metal or non metal
    6·1 answer
  • Can we use water as a solvent to obtain ethyl butyrate?
    13·1 answer
  • What are two human activities that are harmful<br> to birds?
    13·1 answer
  • For a gas sample containing equimolar amounts of carbon monoxideand heliumat 300 K, heliumhas _____________average speed and ___
    5·1 answer
  • Determine the volume, in liters, occupied by 0.050 moles of water vapor at STP.
    12·1 answer
  • Which type of plant would a gardener most likely plant in a shady area of
    13·2 answers
  • A. The sand and water together in the beaker is called a
    12·1 answer
  • How long does it take a person at rest to breathe one mole of air if the person breathes 82.0 mL/s of air that is measured at 25
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!