If the SPF rating is 20 then it means it would provide 20 times the protection instead of no sunscreen and 20 times longer someone would take before the person started to burn or in this case 200 minutes.
Cathode rays are a stream of negatively charged particles or electrons in vacuum tubes. They were first seen by Johann Hittorf in 1869. They are named since they are emitted by electrode or cathode. In order to release the electrons, the electrons should first be detached from the atoms of the cathode.
Answer:
0.482 ×10²³ molecules
Explanation:
Given data:
Volume of gas = 2.5 L
Temperature of gas = 50°C (50+273 = 323 k)
Pressure of gas = 650 mmHg (650/760 =0.86 atm)
Molecules of N₂= ?
Solution:
PV= nRT
n = PV/RT
n = 0.86 atm × 2.5 L /0.0821 atm. mol⁻¹. k⁻¹. L × 323 k
n = 2.15 atm. L /26.52 atm. mol⁻¹.L
n = 0.08 mol
Number of moles of N₂ are 0.08 mol.
Number of molecules:
one mole = 6.022 ×10²³ molecules
0.08×6.022 ×10²³ = 0.482 ×10²³ molecules
Answer: Different plant structure can increase chances of reproduction by the animals and other living organisms in the ecosystem.
Explanation: Plants like flowers can be pollinated by bees . The bees carry the pollen and this can increase chances of reproduction. Plants like plums that have large seeds can increase chances of reproduction by there fruit falling and rotting so the seed can be forced into soil. Different structures of plants can increase chances of reproduction through the animals, soil around the plant, as well as weather .
Answer:
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Explanation:
