I would say that descriptive investigations aren't repeatable because it means that you are only describing something - you ask certain question about something, but do not form a hypothesis at that point yet. So it would be a waste of time to simply ask the same questions over and over again with no hypothesis to prove, which is why these types of investigations cannot be repeated.
Answer:
6.9 hours
Explanation:
In order to solve this problem we'll<u> convert 837 km to miles</u> (another option would be to convert 75 mi/hr to km/hr). To make said conversion we'll use the given <em>conversion factor</em>:
- 837 km *
= 519.88 mi
Finally we <u>calculate the time required to travel said distance</u> at a constant speed of 75 mi/hr:
- 519.88 mi ÷ 75 mi/hr = 6.9 hr
Answer: Option (b) is the correct answer.
Explanation:
Chemical properties are defined as the properties which tend to chemical composition of a substance. Neutral elements with similar number of valence electrons tend to show similar chemical properties as these have same reactivity which actually affects their chemical properties.
This means that elements of the same group tend to show similar chemical properties.
For example, oxygen and sulfur atom are both group 16 elements and they have 6 valence electrons. Therefore, they show similar chemical properties.
Thus, we can conclude that a pair of O and S elements is expected to be most similar in their chemical properties.
Answer:
7.69x
Explanation:
The ionization is the energy necessary to transform an atom in an anion. So, it's the energy it requires to gain an electron.
This ionization occurs for the photoelectric effect - the emission of electrons by metal using photons. So, if the efficiency is 100%, 1 photon can ionize 1 atom, but for an effficiency of 13.0%:
N = 
N = 7.69x
Where N is the number of photons.
Answer:
Krypton.
Explanation:
By Graham's Law:
Rate 1 / Rate 2 = sqrt M2 / sqrt M1
Molecular Mass for Neon is 20.18
so we have:
38 / 77.5 = sqrt 20.18 / sqrt x where x is the unkown gas.
sqrt x = 9.162
x = 83.94.
This gas is Krypton.