Calculate the percent composition by mass of each element in Al(OH)3. Use at least three significant figures.

Chemistry

2 answers:

motikmotik3 years ago

7 0

Answer:

nope nope nope nope nope nope nope nope

serg [7]3 years ago

4 0

Answer:

Al= (27/78)x100

Al= 34.6%

O= (48/78)x100

O= 61.5%

H= (3/78)x100

H= 3.85%

You might be interested in

Which type of reaction is Pb(NO3)2 + 2HCl → PbCl2 + 2HNO3?

Ganezh [65]

Answer:- D. Double- replacement reaction

Explanations:- In general, the decomposition reactions looks like:

$AB\rightarrow A+B$

The given reaction looks different than this and so it is not decomposition reaction.

A single-replacement reaction looks like:

$AB+C\rightarrow AC+B$

Our reaction looks different from this so single-replacement is also not correct.

Synthesis reaction looks exactly opposite to decomposition reaction.

$A+B\rightarrow AB$

The given reaction is different than this and so it is not synthesis reaction also.

A double-replacement reaction looks like:

$AB+CD\rightarrow AD+CB$

In this reaction, the ions are exchanged as could be seen in the general reaction. On reaction side,A is with B and C is with D. On product side, A is with D and C is with B.

The same is happening in the given reaction. Nitrate ion is with lead metal on reactant side and chlorine is with hydrogen, On product side, Chlorine is with lead metal and nitrate ion is with hydrogen. So, ion exchange has taken place here and so this is a double-replacement reaction and choice D is correct.

4 0

3 years ago

When 20.0 g of KI are dissolved in 50.0 mL of distilled water in a calorimeter, the temperature drops from 24.0 °C to 19.0 °C. C

Reil [10]

<h2>Answer:</h2>

<h2>Explanations</h2>

The formula for calculating the amount of heat absorbed by the water is given as:

$\begin{gathered} q=mc\triangle t \\ q=50\times4.18\frac{J}{g^oC}\times(19-24) \\ q=50\times4.18\times(-5) \\ q=-1045Joules \\ q=-1.045kJ \end{gathered}$

Determine the moles of KI

$\begin{gathered} moles\text{ of KI}=\frac{mass\text{ of KI}}{molar\text{ mass of KI}} \\ moles\text{ of KI}=\frac{20g}{166g\text{/mol}} \\ moles\text{ of KI}=0.1205moles \end{gathered}$

Since heat is lost, hence the enthalpy change of the solution will be negative that is: