Answer:
The geologist time scale was formed when scientists studied rock layers and index fossils worldwide. With this information, they placed Earth's rocks in order by relative age. Later, radioactive dating helped determine the exact age of the divisons in the geologic time scale.
This scale is organized by the 4.6 billion years of earth's history into sections based on important changes seen in the geologic record. The largest intervals are called eons, with each eon containing many millions of years.
In precambarian time the processes that affect Earth's surface have lessened the erosion on the surface. Earth was being hit by meteorites every second. Now there is water erosion and there wasn't back then. The surface changes have lessened over time.
Answer:
λ = 2.8 m
Explanation:
Given data:
Frequency of radio wave = 106.7 ×10⁶ Hz
Wavelength of radio wave = ?
Solution:
Formula:
Speed of wave = frequency × wavelength
speed of wave = 3×10⁸ m/s
by putting values,
3×10⁸ m/s = 106.7 ×10⁶ Hz × λ
Hz = s⁻¹
λ = 3×10⁸ m/s / 106.7 ×10⁶ Hz
λ = 3×10⁸ m/s / 106.7 ×10⁶ s⁻¹
λ = 0.028×10² m
λ = 2.8 m
True
Pressure is the force per unit area on an object. The force in the case of air pressure is the weight of the air molecules; therefore, the air pressure is essentially due to gravity pulling down air molecules.
Answer: m= 85.8 g CH2O
Explanation: First step is convert the molecules of CH2O to moles using the Avogadro's Number.
1.72x10²⁴ molecules CH2O x 1 mole CH2O / 6.022x10²³ molecules CH2O
= 2.86 moles CH2O
Next is convert the moles of CH2O to mass using the molar mass of CH2O
2.86 moles CH2O x 30 g CH2O / 1 mole CH2O
= 85.8 g CH2O
The thing that governs whether a reaction is exothermic is the energy given out / used up to break / form the bonds in the reaction.
<span>When two substances react, the bonds in those substances first break up, releasing energy, before re-forming in a different way, taking in energy. The nature of the bonds that are broken up and reformed determines whether more energy is given out (exothermic) or taken in (endothermic)</span>
