Answer:
Explanation:
In an aqueous solution of potassium sulfate (K₂SO₄), the solute is K₂SO₄ and the solvent is water. The percentage by mass describes the grams of solute there are dissolved per 100 grams of solution. It can be calculated as:
mass percentage = (mass of solute/total mass of solution) x 100%
For example, in an aqueous solution which is 2% by mass of K₂SO₄, there are 2 grams of K₂SO₄ per 100 g of solution.
#2. Percent error (or deviation) is calculated as ((TV-EV)/EV))*100
Explanation:
(a) The given data is as follows.
Load applied (P) = 1000 kg
Indentation produced (d) = 2.50 mm
BHI diameter (D) = 10 mm
Expression for Brinell Hardness is as follows.
HB = ![\frac{2P}{\pi D [D - \sqrt{(D^{2} - d^{2})}]}](https://tex.z-dn.net/?f=%5Cfrac%7B2P%7D%7B%5Cpi%20D%20%5BD%20-%20%5Csqrt%7B%28D%5E%7B2%7D%20-%20d%5E%7B2%7D%29%7D%5D%7D)
Now, putting the given values into the above formula as follows.
HB = = ![\frac{2 \times 1000 kg}{3.14 \times 10 mm [D - \sqrt{((10 mm)^{2} - (2.50)^{2})}]}](https://tex.z-dn.net/?f=%5Cfrac%7B2%20%5Ctimes%201000%20kg%7D%7B3.14%20%5Ctimes%2010%20mm%20%5BD%20-%20%5Csqrt%7B%28%2810%20mm%29%5E%7B2%7D%20-%20%282.50%29%5E%7B2%7D%29%7D%5D%7D)
= 
= 200
Therefore, the Brinell HArdness is 200.
(b) The given data is as follows.
Brinell Hardness = 300
Load (P) = 500 kg
BHI diameter (D) = 10 mm
Indentation produced (d) = ?
d = ![\sqrt{(D^{2} - [D - \frac{2P}{HB} \pi D]^{2})}](https://tex.z-dn.net/?f=%5Csqrt%7B%28D%5E%7B2%7D%20-%20%5BD%20-%20%5Cfrac%7B2P%7D%7BHB%7D%20%5Cpi%20D%5D%5E%7B2%7D%29%7D)
= ![\sqrt{(10 mm)^{2} - [10 mm - \frac{2 \times 500 kg}{300 \times 3.14 \times 10 mm}]^{2}}](https://tex.z-dn.net/?f=%5Csqrt%7B%2810%20mm%29%5E%7B2%7D%20-%20%5B10%20mm%20-%20%5Cfrac%7B2%20%5Ctimes%20500%20kg%7D%7B300%20%5Ctimes%203.14%20%5Ctimes%2010%20mm%7D%5D%5E%7B2%7D%7D)
= 4.46 mm
Hence, the diameter of an indentation to yield a hardness of 300 HB when a 500-kg load is used is 4.46 mm.
The reactions based on the absorption and release of the energy are called endothermic and exothermic reactions. The reaction is exothermic.
<h3>What is an exothermic reaction?</h3>
Exothermic reactions are the reaction in which the reactant produces products that release energy from the system to the surroundings. In the reaction bond energy of the reactant is less than the product.
Energy from the system is released in the form of heat, sound, light and electricity. The weak bonds of the compounds are replaced with stronger ones and the standard enthalpy of the reaction is negative.
Therefore, option c. reaction is exothermic is correct.
Learn more about the exothermic reactions here:
brainly.com/question/26616927
You can see my previous answer to this very same question on brainly.com/question/11374210.
The answer is: option D. Response to environment.
Explanation:
As explained, plants (organisms in general) respond to the stimulus provided by the environment.
Such behavior is named tropism. Tropism may be positive or negative.
When the plant's stem bends toward the window, it is showing positive phototropism, which means that the plant growth response to light such that the stems bend toward light, permiting the leaves to receive more light.
I also mention that while the plant's stems posses positive phototropism they posses negative gravitropism and the roots posses positive gravitropism.
Gravitropism is the response of the plant growth to gravity.
Stems grow away from gravity meaning that this is negative gravitropism, but roots grow toward gravity which is positive gravitropism
