To answer the questions,
(1) Activation energy is the amount of energy that is needed for the reaction to proceed, converting the reactant to products. The answer is letter B.
(2) The rate of chemical reaction normally increases as the reactant concentration is increased. The answer is letter C.
13) "..From the ___" My guess would be Sun since it says solar later in the question. Then an example of solar energy would be flashlights, thermostats (etc..)
14) Mechanical
16) Conductors, (Ex. copper, metal)
17) Insulators, most non metallic materials (Ex. cloth, or rubber, plastic)
18) Electrocution
A physical change is when something don't permanently change
Answer:
(c) P and Sb
Explanation:
We can determine the number of valence electrons of an element:
- If it belongs to Groups 1 and 2, the number of valence electrons is equal to the number of group and the differential electron occupies the s subshell.
- If it belongs to the groups 13-18, the number of valence electrons is equal to: "Number of group - 10" and the differential electron occupies the p subshell.
Which pair of elements have the same valence electronic configuration of np³?
(a) O and Se. NO. They belong to the group 16 and the valence electron configuration is ns² np⁴.
(b) Ge and Pb. NO. They belong to the group 14 and the valence electron configuration is ns² np².
(c) P and Sb. YES. They belong to the group 15 and the valence electron configuration is ns² np³.
(d) K and Mg. NO. They belong to the groups 1 and 2 and the valence electron configuration is ns¹ and ns².
(e) Al and Ga. NO. They belong to the group 13 and the valence electron configuration is ns² np¹.
Answer:
Pure iron sulfide is homogeneous (uniform in appearance and properties), shows constant composition (a consistent ratio of iron to sulfur throughout any sample of it, large or small), consists of molecules all of one type, is no longer separable into two separate substances without another chemical reaction, and is .
Explanation:
Mixtures in two or more phases are heterogeneous mixtures. ... The exception would be solutions that contain another phase of matter. For example, you can make a homogeneous solution of sugar and water, but if there are crystals in the solution, it becomes a heterogeneous mixture.
