Answer:
D. Existing skin cells near the injury reproduced to make new cells.
It is physical change because ? has changed alone not with chemicals
Let's consider water.
Regardless of what form it turns into, the mass should remain the same.
It's the same H20.
Add some heat and it becomes water vapor,
cool it down a bit and it becomes ice.
if you make it just right, it becomes water again.
A chemical change would involve the one or more element(s) changing into a different solution all together.
It cannot be reversed unless you use electrolysis or some other method.
Concentration: 2.5% w/v
Concentration w/v % = [mass of solute / volume of solution ] * 100
=> mass of solute = concentration w/v * volume of solution / 100
=> mass of solute = 2.5 * 750 ml / 100 = 18.75 grams
Also, using proportions you get to the same result:
2.5% w/v => 2.5 grams of NaOH / 100 ml of water
=> 2.5 grams of NaOH / 100 ml water = x grams of NaOH / 750 ml water
=> x grams of NaOH = 750 ml water * 2.5 grams of NaOH / 100 ml water
=> x = 18.75 grams of NaOH
Answer = 18.75 grams of NaOH
M
350 mL = 0.350 L
245.0g H2SO4 / 98.08 g/mol H2SO4
= 2.5 mol H2SO4
2.5 mol H2SO4 / 0.350 L = 7.14 M
