Answer: (2) decreasing the concentration of HCl(aq) to 0.1 M
Explanation: Rate of a reaction depends on following factors:
1. Size of the solute particles: If the reactant molecules are present in smaller size, surface of particles and decreasing the size increases the surface area of the solute particles. Hence, increasing the rate of a reaction.
2. Reactant concentration: The rate of the reaction is directly proportional to the concentration of reactants.
3. Temperature: Increasing the temperature increases the energy of the molecules and thus more molecules can react to give products and rate increases.
(1) Increasing the initial temperature to 25°C will increase the reaction rate.
(2) Decreasing the concentration of HCl(aq) to 0.1 M will decrease the reaction rate due to lesser concentration.
(3) Using 1.2 g of powdered Mg will increase the reaction rate due to large surface area.
(4) Using 2.4 g of Mg ribbon will increase the reaction rate due to high concentration of reactants.
<span>The student should
follow following steps to make 1 L of </span>2.0 M CaCl₂.<span>
<span>
1. First he should
calculate the number of moles of 2.0 M CaCl</span></span>₂ in 1 L solution.<span>
</span>Molarity of the solution = 2.0 M<span>
Volume of solution which should be prepared = 1 L
Molarity =
number of moles / volume of the solution
Hence, number of moles in 1 L = 2 mol
2. Find
out the mass of dry CaCl</span>₂ in 2 moles.<span>
moles =
mass / molar mass
Moles of CaCl₂ =
2 mol</span><span>
Molar mass of CaCl₂ = </span><span>110.98 g/mol
Hence, mass of CaCl</span>₂ = 2 mol x <span>110.98 g/mol
= 221.96
g
3. Weigh the mass
accurately
4. Then take a cleaned and dry1 L volumetric flask and place a funnel top of it. Then carefully add the salt into the volumetric flask and
finally wash the funnel and watch glass
with de-ionized water. That water also should be added into the volumetric
flask.
5. Then add some
de-ionized water into
the volumetric flask and swirl well until all salt are
dissolved.
<span>6. Then top up to
mark of the volumetric flask carefully.
</span></span>
7. As the final step prepared solution should be labelled.
Answer:
1. There are so many ethical concerns about biotechnology, some Ethical issues that arise from the application of modern biotechnologies include:
Discrimination of individuals because of their health or health history as a result of knowing their genetic information, minimizing harms while maximizing benefits, Interference with nature, privacy.
2. a. Plants (maize, rice)
b. Fish (GloFish)
3. For individuals, biotechnology has helped in the prevention and treatment of a wide range of diseases. For society, biotechnology saves time, improves the health and quality of food through a reduction in the use of pesticides and it can create new viruses and bacteria that cause diseases. Biotechnology could address global change since more genetically modified plants are grown.
Explanation:
the answer and the working out is shown above, hope it helps.
Explanation:
The scientists used the term electromagnetic spectrum to describe the entire range of light that exists in the universe. From gamma rays to radio waves, most of the light present in the universe invisible to us.
The electromagnetic spectrum describes all the wavelengths of light. It explores an otherwise invisible universe, from an exploding stars to the dark nebulae.
The electromagnetic spectrum that consists of radio waves (used in commercial television and radios, radar, microwaves ), infrared radiation, visible light, gamma rays, x-rays and ultraviolet radiation rays. All the wavelengths and frequencies of the electromagnetic spectrum is used in spectroscopy.
