41.38 % Mg
55.17 % O
3.45 % H
Explanation:
What is the percent composition of magnesium hydroxide Mg(OH)₂?
To find the percent composition we follow the next algorithm.
First we calculate the molar mass of Mg(OH)₂:
molar mass of Mg(OH)₂ = molar mass of Mg × 1 + molar mass of O × 2 + molar mass of H × 2
molar mass of Mg(OH)₂ = 24 × 1 + 16 × 2 + 1 × 2 = 58 g/mole
Now we devise the next reasoning:
if in 58 g of Mg(OH)₂ there are 24 g of Mg, 32 g of O and 2 g of H
then in 100 g of Mg(OH)₂ there are X g of Mg, Y g of O and Z g of H
X = (100 × 24) / 58 = 41.38 % Mg
X = (100 × 32) / 58 = 55.17 % O
X = (100 × 2) / 58 = 3.45 % H
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percent composition
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Answer:
There is 17,114825 g of powdered drink mix needed
Explanation:
Step 1 : Calculate moles
As given, the concentration of the drink is 0.5 M, this means 0.5 mol / L
Since the volume is 100mL, we have to convert the concentration,
⇒0.5 / 1 = x /0.1 ⇒ 0.5* 0.1 = x = 0.05 M
This means there is 0.05 mol per 100mL
e
Step 2 : calculate mass of the powdered drink
here we use the formula n (mole) = m(mass) / M (Molar mass)
⇒ since powdered drink mix is usually made of sucrose (C12H22O11) and has a molar mass of 342.2965 g/mol.
0.05 mol = mass / 342.2965 g/mol
To find the mass, we isolate it ⇒0.05 mol * 342.2965 g/mol = 17,114825g
There is 17,114825 g of powdered drink mix needed
The correct answer is: [C]: "polar" .
_____________________________________________________
" Water " ; which is: " H₂O " ;
_____________________________________________________
is a:
_____________________________________________________
— polar; → {eliminate: "Choice [A]: "non-polar"} ;
→ {and consider: "Choice: [C]: "polar" } ;
— covalent; → {not "ionic"; eliminate: "Choice: [B]: "ionic"} ;
— uncharged; → {neutral compound; not "charged" —but "balanced"} ;
→ {Note: " H ⁺ , O ²⁻ ; → " H₂O " } ;
→ The "charges" balance/ cancel out.
→ {eliminate: "Choice: [D]: "charged" .}.
_______________________________________________________
— compound.
_______________________________________________________
The correct answer is: [C]: "polar" .
_______________________________________________________
Answer:
One
Explanation:
Trailing zeros in a number are not significant unless they follow a decimal point.
If you want to specify a different number of significant figures, you can use a decimal point.
For example,
2.0 × 10³ = two significant figures
2.00 × 10³ = three significant figures
2.000 × 10³ = four significant figure
2000. = four significant figures
