Answer:- 448 mL of hydrogen gas are formed.
Solution:- It asks to calculate the volume of hydrogen gas formed in milliliters at STP when 0.020 moles of magnesium reacts with excess HCl acid. The balanced equation is:
There is 1:1 mol ratio between Mg and hydrogen gas. So, the moles of hydrogen gas is also equals to the moles of Mg reacted.
moles of Hydrogen gas formed = 0.020 mol
At STP, volume of 1 mol of the gas is 22.4 L. We need to calculate the volume of 0.02 moles of hydrogen gas.
= 0.448 L
They want answer in mL. So, let's convert L to mL using the conversion formula, 1L = 1000mL
= 448 mL
So, 0.020 moles of magnesium would produce 448 mL of hydrogen gas at STP on reacting with excess of HCl acid.
Answer:
Cells are uncountable becasue they move around your body, make up your skin and other organs as well. And because when you grow, the cells multiply, and that makes it very hard for scientists to count cells in a human's body.
Explanation:
Hope this helped!
Answer:
hecto-
Explanation:
The prefix value of 100 is hecto therefore 100X can be called hecto-x.
Such prefixes as this are expressed in the order of tens. Units generally exists scientifically in multiples and submultiples form using prefixes.
For the multiples:
10 deca(da)
100 hecto(h)
1000 kilo(k)
1000000 mega(M)
1000000000 giga(G)
It takes 33.4 s for the concentration of A to fall to one-fourth of its original value.
A <em>half-life</em> is the time it takes for the concentration to fall to half its original value.
Assume the initial concentration is 1.00 mol/L. Then,
The concentration drops to one-fourth of its initial value in two half-lives.
∴ Time = 2 × 16.7 s = 33.4 s
