Safety glasses should be worn any time you are doing an experiment, especially one that involves chemicals or chemical reactions. They prevent chemicals or other materials from getting on or in your eye, and can prevent anything from mild discomfort to permanent blindness.
Some pairs of safety glasses have magnifying glasses on them, similar to bifocals. They can be used to more carefully examine something in an experiment.
Answer:
The correct option is: b. pH 6.4-8.0
Explanation:
Phenol red is a weak acid that is used as a pH indicator and exists in the form of stable red crystals.
<u>The color of the phenol red solution changes from yellow to red when the change in pH is observed. The color of phenol red transitions from yellow to red when the pH is 6.8 - 8.2 or 6.4 - 8.0</u>
Above the pH of 8.2, the phenol red solution turns a bright pink in color.
Answer:
Explanation:
H ₂ S O ₄ + 2 N a O H ⟶ 2 H ₂ O + N a ₂ S O ₄
29.09 mL of 0.639 M N a O H is mixed with 213.8 mL of H ₂ S O ₄
Let the concentration of H ₂ S O ₄ be S₂ .
In terms of normal or equivalent solution is will be 2 N solution
From the formula S₁ V₁ = S₂ V₂
= 29.09 x .639 = 213.8 x S₂
S₂ = .087 N solution
In terms of molar solution it will be .087 / 2 M
= .0435 M
Answer:
copper will reach to higher temperature first.
Explanation:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
The substances with higher value of specific heat capacity require more heat to raise the temperature by one degree as compared the substances having low value of specific heat capacity.For example,
The specific heat capacity of copper is 0.386 j/g. K and for aluminium is 0.900 j/g.K. So, aluminium take a time to increase its temperature by one degree by absorbing more heat while copper will heat up faster by absorbing less amount of heat.
Consider that both copper and aluminium have same mass of 5g and change in temperature is 15 K. Thus amount of heat thy absorbed to raise the temperature is,
For copper:
Q = m.c. ΔT
Q = 5 g× 0.386 j/g K × 15 K
Q = 28.95 j
For aluminium:
Q = m.c. ΔT
Q = 5 g× 0.900 j/g K × 15 K
Q = 67.5 j
we can observe that aluminium require more heat which is 67.5 j to increase its temperature. So it will reach to higher temperature later as compared to copper.
