12 pens for writing chemical formulas cost
12*2=24 dollars
12 pads cost
12*3=36 dollars
1)
12*2=24
12*3=36
2)
12*2+12*3=60 dollars
3) 12*(3+5)=60 dollars
Answer:
1.758 x 10⁻¹¹.
Explanation:
∵ pH = - log[H⁺].
∴ 5.47 = -log[H⁺].
log[H⁺] = -5.47.
∴ [H⁺] = 3.388 x 10⁻⁶ M.
∵ [H⁺] = √(Ka.C)
∴ [H⁺]² = Ka.C
<em>∴ Ka = [H⁺]²/C </em>= (3.388 x 10⁻⁶)²(0.653) = <em>1.758 x 10⁻¹¹.</em>
Answer:
First option
Explanation:
Students 1 and 2 have precise measures yet is is not accurate since they measure around 5.
Answer:
0.54 g of Pb in 60 m³ of [Pb] = 9 ppb
Explanation:
We need to know, that ppb is a sort of concentration that indicates (in value of volume) ng / mL (ppb = parts per billion)
9 ppb means that 9 ng are contained in 1mL of solution
We know that 1mL = 1 cm³
Let's convert 60 m³ to cm³ → 60 m³ . 1×10⁶ cm³ / 1m³ = 6×10⁷ cm³
Then, we can make a rule of three:
1 cm³ has 9 ng of Pb
Therefore in 6×10⁷ cm³ we must have ( 6×10⁷ cm³ . 9ng) / 1 cm³ =
5.4×10⁸ ng
We convert ng to g → 5.4×10⁸ ng . 1 g / 1×10⁻⁹ ng = 0.54 g
Answer:
The conditions for hurricanes differ from the conditions of tornadoes because of D, Tornadoes form over land, while hurricanes form over bodies of water.
Explanation:
Hurricanes form over warm water in tropical ocean settings and tornadoes form over land within storms.
