For instance a white girl walks in the sunlight her skin is really white this is one common reason white people tend to get freckles now if a black person were to go outside they wouldnt receive freckles from direct sunlight
Answer:
D. In a low-pressure system, air sinks, creating fair weather. In a high-pressure system, air rises, creating storms.
Explanation:
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Answer:
4.81×10¹⁰ atoms.
Explanation:
We'll begin by converting 3.2 pg to Ca to grams (g). This can be obtained as follow:
1 pg = 1×10¯¹² g
Therefore,
3.2 pg = 3.2 pg × 1×10¯¹² g / 1 pg
3.2 pg = 3.2×10¯¹² g
Therefore, 3.2 pg is equivalent to 3.2×10¯¹² g
Next, we shall determine the number of mole in 3.2×10¯¹² g of Ca. This can be obtained as follow:
Mass of Ca = 3.2×10¯¹² g
Molar mass of Ca = 40.08 g/mol
Mole of ca=.?
Mole = mass /molar mass
Mole of Ca = 3.2×10¯¹² / 40.08
Mole of Ca = 7.98×10¯¹⁴ mole.
Finally, we shall determine the number of atoms present in 7.98×10¯¹⁴ mole of Ca. This can be obtained as illustrated below:
From Avogadro's hypothesis,
1 mole of Ca contains 6.02×10²³ atoms.
Therefore, 7.98×10¯¹⁴ mole of Ca will contain = 7.98×10¯¹⁴ × 6.02×10²³ = 4.81×10¹⁰ atoms.
Therefore, 3.2 pg of Ca contains 4.81×10¹⁰ atoms.
Answer: 15 grams of salt are there in 5 L of solution.
Explanation:
Concentration of a solution is defined as the number of grams of solute dissolved per liter of the solution.
Given : Concentration of solution : 3 g/L
1 Liter of solution contains = 3 gram of salt
Thus 5 L of solution contains = 
Thus 15 grams of salt are there in 5 L of solution.
Answer:
The correct option is option E
Addition to the carbonyl by a nucleophile is followed by loss of the leaving group.
Explanation:
Substitution reaction that involves nucleophile and acyl group is called nucleophilic acyl substitution reaction.
Generally alcohol, amine or enolate group act as nuceophile. The nucleophile displaces the acyl group of acyl haide, anhydride or ester.
Mechanism of acyl substitution reaction
First step is the addition of nucleophile to the carbonyl carbon results in the formation of a tetrahedral derivatives.
Second step is the removal of leaving group
Hence, the correct option is option E
