The pollution in the cities darkened basically everything, meaning the lighter colored moths were more visible, and were targeted. The dark ones, as a rule, lived whereas the light ones did not. This is an example of evolution.
Answer: Alkali metals, halogens, noble gases
Explanation:
Ionic compounds are made of ions- charges. In LiF and NaCl, the first element has a +1 and the second element has a charge of -1. Elements that are +1 are alkali metals and elements that are -1 are halogens. Noble gases have full octets in their outermost valence shell, and since they're full it's so stable so it doesn't react with anything.
Living organisms contain relatively large amounts of oxygen, carbon, hydrogen, nitrogen, and sulfur (thesefive elements are known as the bulk elements), along with sodium, magnesium, potassium, calcium, chlorine, and phosphorus (these six elements are known as macrominerals).
Answer:
Elements with low ionization energies.
Explanation:
The ionization energy of an atom reffers to the amount of energy that is required to remove an electron from the gaseous form of that atom or ion.
The greater the ionization energy, the more difficult it is to remove an electron. The ionization energybis one of the indicator that shows the reactivity of an element. Elements with a low ionization energy such as metals are usually reffered to as a reducing agents and form cations, this give metals the tendency to
give away their valence electrons when bonding, whereas non-metals tend to take electrons.
Metallic elements have different properties such as shiny, heat and electricity conductivity . They are malleable and ductile Some metals, such as sodium, are soft and can be cut with a knife. while some are very hard such as iron.
Answer:
5 × 10^-4 L
Explanation:
The equation of the reaction is;
2KClO3 = 2KCl + 3O2
Number of moles of KClO3 = 13.5g/122.5 g / mol = 0.11 moles
From the stoichiometry of the reaction;
2 moles of KClO3 yields 3 moles of O2
0.11 moles of KClO3 yields 0.11 × 3/2 = 0.165 moles of oxygen gas
From the ideal gas equation;
PV= nRT
P= 85.4 × 10^4 KPa
V=?
n= 0.165
R= 8.314 J K-1 mol-1
T= 40+273 = 313K
V= 0.165 ×8.134 × 313/85.4 × 10^4
V=429.4/85.4 × 10^4
V= 5 × 10^-4 L
