question 1
moles = mass/molar mass of Al(OH)3
convert Kg to g
that is 1.09 x 1000=1090g
moles is therefore=1090g/78(molar mass of Al(OH)3)= 13.974 moles
question 2
moles=2.55g/327.2(molar mass of Pb(CO3)2= 7.79 x 10^-3 moles
from avogadro constant
1moles=6.02 x10^23 formula units
what about 7.79 x 10 ^-3
={(7.79 x 10^-3)moles x ( 6.02 x10^23)} /1 mole=4.69 x10^21 formula units
V = 75 mL = 0,075 L = 0,075 dm³
C = 2.1M
n = ?
---------------
C = n/V
n = C×V
n = 2.1×0,075
n = 0,1575 mol
--------
mKCl: 39+35.5 = 74,5 g/mol
74,5g --------- 1 mol
Xg ------------- 0,1575 mol
X = 74,5×0,1575
X = 11,73375g KCl
:•)
The solution to the problem (102 900 ÷ 12) + (170 × 1.27) = 8800.
<u>Explanation</u>:
Step 1.
Evaluate the expressions inside the parentheses (PEMDAS)
102 900 ÷ 12 = 8575
170 × 1.27 = 215.9
In multiplication and division problems, your answer can have no more significant figures than the number with the fewest significant figures.
Thus, the underlined digits are not significant, but we keep them in our calculator to avoid roundoff error.
Step 2.
Do the addition (PEMDAS).
8575 + 215.9 = 8790.9
Everything that you add to an insignificant digit gives an insignificant digit as an answer.
Thus, the underlined digits are not significant.
We must drop them and round up the answer to 8800.
Answer:
H2 is Molecular hydrogen. It is a molecule of hydrogen that consists of two hydrogen atoms bonded together by one single bond
Explanation:
