Experimental investigations<span> involve a process in which a "fair test" is designed and variables are actively manipulated, controlled, and measured in an effort to gather evidence to support or refute a </span>causal relationship<span>. Experimental investigations have a control group which does not receive any treatment. A classic example is "What is the effect of light color on plant growth?" In this experiment, the variable color of light is changed by the student. The student may compare red light to green light to natural light.
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Answer:
Correct answer is b) convex mirror
Explanation:
A convex mirror, which bulges outward, reflects at a wider angle near its edges than at its center, creating a slightly distorted image that's smaller than actual size. Convex mirrors have many uses. The smaller size of the images means that you can see more with these surfaces, hence their use in safety mirrors.
This is the answer of your question. ☺
Answer:
k is 3,18*10⁻² s⁻¹ at 75°C
Explanation:
following Arrhenius equation:
k= k₀*e^(-Ea/RT)
where k= rate constant , k₀= frequency factor , Ea= activation energy , R= universal gas constant T=absolute temperature
then for T₁=25°C =298 K
k₁= k₀*e^(-Ea/RT₁)
and for T₁=75°C = 348 K
k₂= k₀*e^(-Ea/RT₂)
dividing both equations
k₂/k₁= e^(-Ea/RT₂+Ea/RT₁ )
k₂= k₁*e^[-Ea/R*(1/T₂-1/T₁ )]
replacing values
k₂= k₁*e^[-Ea/R*(1/T₂-1/T₁ )] = 4,7*10⁻³ s⁻¹ *e^[-33.6*1000 J/mol /8.314 J/molK*(1/ 348 K -1/298 K )] = 3,18*10⁻² s⁻¹
thus k is 3,18*10⁻² s⁻¹ at 75°C
