Ultraviolet as ultraviolet light waves are around 420 nm like stated in the photo
Answer:
D. Halogens
Explanation:
All elements in these groups have 7 valence electrons, meaning their electronegativity is the highest among the elements.
= 9.1 × 10^6
(scientific notation)
= 9.1e6
(scientific e notation)
= 9.1 × 10^6
(engineering notation)
(million; prefix mega- (M))
= 9100000
<span>(real number)</span>
Answer:
A rule of thumb is that 1.5 lbs. of baking soda per 10,000 gallons of water will raise alkalinity by about 10 ppm. If your pool's pH is tested below 7.2, add 3-4 pounds of baking soda. If you're new to adding pool chemicals, start by adding only one-half or three-fourths of the recommended amount.
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