HCl and NaOH react in a 1:1 ratio, meaning that 1 H+ from HCl will react with 1 OH- from NaOH. Knowing this, and that molarity is mol/liter, all we need to do is use what we have available. First we must find the mols of HCl in our solution, so we set up the following equation in the following steps:
1. 24.75mL x (0.359mol NaOH / 1000mL) = 8.885 x 10^-3mol NaOH
This is done in order to find the mols of NaOH to convert to mols of HCl.
2. 8.885x10^-3mol NaOH x (1 mol HCl/1mol NaOH) = 8.885 x 10^-3mol HCl
Here we just used the mols of NaOH we found to convert to mols of HCl using the 1:1 ratio described earlier.
From the mols of HCl all we have to do is divide by the amount of liters in the solution. Since we started with 10mL HCl and added 24.75mL NaOH, the total volume is 34.75mL = 0.03475L. So:
8.885 x 10^-3mol HCl/0.03475L = 2.557 x 10^-1M HCl
However, this is the molarity of the HCl and NaOH solution, not the original HCl solution. Using the dilution equation M1V1=M2V2, we can solve for the original molarity.
M1 = the molarity of our HCl in the titrated mixture (2.557 x 10^-1M HCl)
V1 = the total volume that our mixture has (34.75mL = 0.03475L)
M2 = what we're trying to find
V2 = the amount of the original HCl that we had (10mL = 0.010L)
Simply solving for M2 gives us:
M2 = (M1V1) / V2 or:
M2=((2.557 x 10^-1) x 0.03475L) / 0.010L = 8.89 x 10^-1M HCl. That is your answer.
Answer:
- <em>On the atomic level, energy and matter exhibit the characteristics of </em><u>both waves and particles.</u>
Explanation:
The dual behavior of subatomic particles as waves and particles is known as the wave - particle duality.
And this principle is the basis of the quantum theory.
Such principle is widely applied to the electrons; i.e., the electrons posses wave and particle propeties, which must be understodd as that some of their properties may be explained as if they were particles and others as if they were waves.
For example, from the particle point of view electrons have mass. You can find in internet that the mass of one electron is about 9.1093837015×10⁻³¹ kg or about 1/1836 times the mass of one proton.)
Since, the point of view of the wave characteristics, electrons have wavelength, Louis de Broglie deduced the equation that relates the wavelength and the mass, through this realtion:
- Wavelength (λ) = Planck’s constant (h) divided by the product of the mass (m) and the the speed (v) of the particle.
λ = h / mv
Answer:
Option D. Iron and sulfur react to form iron sulfide
Explanation:
Reaction of iron with sulphur is a chemical property and not a physical property.
The starting material or materials for a chemical reaction are referred to as the reactants. The substance or substances produced from a chemical reaction are called products. Sometimes a secondary product, a byproduct, can also be created at the same time as the desired product(s).
Not every chemical reaction occurs in the same way. There are different types of chemical reactions, including synthesis reactions, decomposition reactions, and displacement reactions. In this experiment, a decomposition reaction takes place. During a decomposition reaction, a compound breaks apart into two or more products. Most decomposition reactions need an outside source of energy in order to take place.
Hydrogen peroxide is not a very stable compound, so it slowly decomposes into water and oxygen gas under normal conditions. In this reaction, yeast is used as a catalyst. A catalyst is a substance that helps to change the rate of a reaction. During the reaction, the catalyst is not consumed. As a result, the yeast makes the reaction occur much faster; it causes the hydrogen peroxide to break down and release the oxygen gas much faster.
The soap is used to help us “see” the reaction. Bubbles of oxygen become trapped in the soap, creating foam. The reaction occurs so quickly, releasing so much gas and creating so much foam, that the foam begins to flow out of the bottle. The result of this reaction looks like toothpaste being squeezed out of a tube.
In addition, the bottle will feel warm to the touch because the reaction is exothermic. An exothermic reaction or process is one that gives off energy. In contrast, an endothermic reaction or process is one that requires or absorbs energy.
HYPOTHESIS
uAdding yeast to hydrogen peroxide
will cause the hydrogen peroxide to
decompose quickly into water and oxygen gas, creating foam as the gas becomes trapped in liquid dish soap and pushes upward out of the bottle.
FORMULAS & EQUATIONS
Hydrogen peroxide is a relatively clear liquid substance. It is soluble in water and is often sold as a mixture of H2O2 in water. The hydrogen peroxide used in this experiment is actually a 6% solution of H2O2 in water.
The chemical formula for hydrogen peroxide is H2O2.
Hydrogen peroxide naturally decomposes into water and oxygen gas. The reaction is shown by the following equation:
2H2O2 (aq)g2H2O (l) + O2 (g)
The rate of the reaction can be increased by introducing a catalyst. In this experiment, the catalyst is yeast. Yeast is a microorganism that is part of the fungi family. Therefore, in the equation below, the catalyst is indicated above the arrow.
yeast
2H2O2 (aq) g 2H2O (l) + O2 (g)
The hydrogen peroxide used in the experiment is
actually a mixture of water and hydrogen peroxide.
CONNECT TO THE YOU BE THE CHEMIST CHALLENGE
For additional background information, please review CEF’s Challenge study materials online at http://www.chemed.org/ybtc/challenge/study.aspx.
• Additional information on elements, compounds, and physical and chemical changes can be found in the Classification of Matter section of CEF’s Passport to Science Exploration: The Core of Chemistry.
• Additional information on chemical reactions can be found in the Chemical Reactions section of CEF’s Passport to Science Exploration: Chemistry
Answer: true
explanation:
