All categories

2 years ago

What is the chemical reaction when cooking pasta

2 answers:

8 0

Science is all around us, even right in our own kitchens! You might not have thought about the science of a spaghetti dinner. Science begins when we heat the water to boil our pasta. As the water boils, it turns to gas. The matter is changing from its liquid state to gas. Condensation along with evaporation is happening before our eyes. These are examples of physical changes, where the basic composition of substances remains the same. We add the pasta noodles to cook but it doesn’t end there. A chemical reaction is taking place here as well. By boiling the pasta the molecular structures of the starches change so that pasta changes from hard and brittle to soft, chewy and delicious!

Maksim231197 [3]2 years ago

3 0

The molecular structures are beginning to change changing it from hard to soft

You might be interested in

The solubility of KCl is 3.7 M at 20 °C. Two beakers each contain 100. mL of saturated KCl solution: 100. mL of 4.0 M HCl is add

JulijaS [17]

Answer:

a)The Ksp was found to be equal to 13.69

Explanation:

Terminology

Qsp of a dissolving ionic solid — is the solubility product of the concentration of ions in solution.

Ksp however, is the solubility product of the concentration of ions in solution at EQUILIBRIUM with the dissolving ionic solid.

Note that if Qsp > Ksp , the solid at a certain temperature, will precipitate and form solid. That means the equilibrium will shift to the left in order to attain or reach equilibrium (Ksp).

Step-by-step solution:

To solve this:

#./ Substitute the molar solubility of KCl as given into the ion-product equation to find the Ksp of KCl.

#./ Find the total concentration of ionic chloride in each beaker after the addition of HCl. We pay attention to the amount moles present at the beginning and the moles added.

#./ Find the Qsp value to to know if Ksp is exceeded. If Qsp < Ksp, nothing will precipitate.

a) The equation of solubility equilibrium for KCL is thus;

KCL_(s) ---> K+(aq) + Cl- (aq)

The solubility of KCl given is 3.7 M.

Ksp= [K+][Cl-] = (3.7)(3.7) =13.69

The Ksp was found to be equal to 14.

In pure water KCl

Ksp =13.69 KCl =[K+][Cl-]

Let x= molar solubility [K+],/[Cl-] :. × , x

Ksp =13.69 = [K+][Cl-] = (x)(x) = x²

x= √ 13.69 = 3.7 M moles of KCl requires to make 100mL saturated solutio

37M moles/L

The Ksp was found to be equal to 14.

4.0 M HCl = KCl =[K+][Cl-]

Let y= molar solubility :. y, y+4

Ksp =13.69= [K+][Cl-] = (y)(y*+4)

* - rule of thumb

Ksp =13.69= [K+][Cl-] = (y)(y*+4)= y(4)

13.69=4y:. y= 3.42 moles/100mL

y= 34.2moles/L

8 M HCl = KCl =[K+][Cl-]

Let b= molar solubility :. B, b+8

Ksp =13.69= [K+][Cl-] = (b)(b*+8)

* - rule of thumb

Ksp =13.69= [K+][Cl-] = (b)(b*+8)= b(8)

13.69=8b:. b= 1.71 moles/100mL

17.1 moles/L

Therefore in a solution with a common ion, the solubility of the compound reduces dramatically.

8 0

2 years ago

Read 2 more answers

Calculate the pH of a buffer solution prepared by dissolving 0.20 mole of cyanic acid (HCNO) and 0.80 mole of sodium cyanate (Na

Afina-wow [57]

The pH of a buffer solution : 4.3

<h3>Further explanation</h3>

Given

0.2 mole HCNO

0.8 mole NaCNO

1 L solution

Required

pH buffer

Solution

Acid buffer solutions consist of weak acids HCNO and their salts NaCNO.

$\tt \displaystyle [H^+]=Ka\times\frac{mole\:weak\:acid}{mole\:salt\times valence}$

valence according to the amount of salt anion

Input the value :

$\tt \displaystyle [H^+]=2.10^{-4}\times\frac{0.2}{0.8\times 1}\\\\(H^+]=5\times 10^{-5}\\\\pH=5-log~5\\\\pH=4.3$

7 0

2 years ago

calculate the specific heat capacity for gold n 105 joules are required to heat 30.0 grams of gold from 27.7c to 54.9c

Pepsi [2]

<u>Answer:</u>

<em>The specific heat capacity for gold in 105 joules which are required to heat 30.0 grams of gold is 0.129 J/(g℃)</em>

<u>Explanation:</u>

We make use of the formula

$Q=m \times c \times \Delta T$

where

∆T = final T - initial T

= 54.9℃ - 27.7℃ = 27.2℃

Q is the heat energy in Joules = 105J

c is the specific heat capacity = ?

m is the mass of Gold = 30.0g

$Q=m \times c \times \Delta T$

Rearranging the formula

$c= \frac {Q}{(m\times \Delta T)}$

$= \frac {105J}{(30.0g \times 27.2 ^\circ{C})}\\\\= \frac {105J}{(816g^\circ{C})}$

So,

c = 0.129 J/(g℃)

(Answer)

7 0

2 years ago

a metal worker uses a cutting torch that operates by reacting acetylene gas, C2H2(g), with oxygen gas, O2(g), as shown in the un

harkovskaia [24]

Answer:

650 grams

Explanation:

Given that acetylene gas reacts with oxygen to produce caobon dioxide, water and heat and the unbalnced equation is

$C_2H_2(g)+O_2(g) \rightarrow CO_2(g) + H_2O(g)+ heat$

Gram-formula mass of $C_2H_2= 26$ g/mol

So, mass of 1 mole of acelylene is 26 grams

Therefore, mass of 25 moles of acelylene=25x26=650 grams

Hence, the mass of 25 moles of acelylene is 650 grams

8 0

2 years ago

Read 2 more answers

In which of the following aqueous solutions would you expect AgI to have the highest solubility? In which of the following aqueo

telo118 [61]

Answer:

Solubility indicates the maximum amount of a substance that can be dissolved in a solvent at a given temperature. Such a solution is called saturated,it is calculated by dividing the mass of the compound by mass of the solvent then multiply by the molar concentration.

molar mass of solvent (Agl)= 107.8682 + 126.90447 = 234.77267g/mol

For 0.038M of Nal

molar mass of Nal compound= 22.99 + 126.90447 = 149.89447g/mol

solubility = [ 149.89447 / 234.77267] * 0.038 = 0.024

For 0.05M of AgNO3

molar mass of AgNO3 compound = 107.8682 + 14.01 + 3(16) = 169.8782g/mol

solubility = [169.8782 / 234.77267] * 0.05 = 0.036

For 0.025M of KI

molar mass of KI compound = 39.0983 + 253.8089 = 292.9072g/mol

solublity = [292.9072 / 234.77267] * 0.025 = 0.031

For 0.0125M of Lil

molar mass of Lil compound = 6.941 + 253.8089 = 260.7499g/mol

solubility = [260.7499 / 234.77267] * 0.0125 = 0.014

Therefore the solution with the highest solubility is 0.05M of AgNO3

5 0

2 years ago