Answer:
Alkali metals
Explanation:
The alkali metals are a group of metallic elements which are present in the first group of the periodic table. In other words, they are present in group 1 of the periodic table. These elements have one electron in their valence shell, the reason why they are placed in group 1.
They ionize by losing one electron to achieve the configuration of the nearest Noble gas or inert gas. Because they need to offset only one electron in their outermost shell, they are very chemically reactive and hence rarely occur in the free state.
Examples of elements in this group include lithium, potassium and sodium. They each have one electron only in their outermost shells.
The three mass value measure are precise mass
<u>explanation</u>
precise mass is term use to describe data from experiment that have been repeated several times. An experiment that yield tightly grouped set of data it has a high precision. 8.93 , 8.94 and 8.92 are precise mass since they have repeated severally
No, x-rays do not travel slower than infrared radiation or even the opposite. Both are travelling in vacuum therefore they travel at same speed. They differ in the frequency of the electromagnetic waves.
Gravity is the force that keeps the planets in orbit.
Answer:
Explanation:
4NH₃ (g) + 3O₂ (g) ⇒ 2N₂ (g) + 6H₂ O(1)
Δ
ΔH r =(2ΔH f(N 2 )+6ΔH f (H 2 O(l)))−(4ΔH f (NH 3 (g))+3ΔH f (O 2 (g)))
ΔH rex =[2×0+6×(−286)]−[4×(−46)+3×0]=−1716+186
ΔH rex =−1532kJ/mol
Thermodynamics is a branch of physical chemistry that studies heat and its effects and interactions. Governed by the four main laws, thermodynamics plays a huge role in physics and chemistry, and is also responsible for the law of conservation of energy, a fundamental rule in science.
