All categories

3 years ago

if you are given one element name and % by mass, how do you find the other element in the compound? give example plz

Chemistry

1 answer:

Marta_Voda [28]3 years ago

6 0

The percentage of elements in the compound is determined from the number of elements in the compound

<h3>Further explanation </h3>

Proust states the Comparative Law that compounds are formed from elements with the same Mass Comparison so that compounds have a fixed composition of elements

$\tt \%A~in~A_xB_y=\dfrac{x\times Ar~A}{MW~A_xB_y}\times 100\%$

$\tt \%B~in~A_xB_y=\dfrac{y\times Ar~B}{MW~A_xB_y}\times 100\%$

Example

% Lithium (Li) in Li₂CO₃(lithium carbonate)

Ar of Li = 6.941 g/mol

MW of Li₂CO₃ = 73.891 g/mol

$\tt \%Li=\dfrac{2.Ar~Li}{MW~Li_2CO_3}\times 100\%\\\\\%Li=\dfrac{2\times 6.941}{73.891}\times 100\%=18.79\%$

You might be interested in

1) A light bulb takes in 30 of energy per second. It transfers 3j as use

natta225 [31]

Answer:

$\boxed{\text{10 \%}}$

Explanation:

The formula for efficiency is

$\begin{array}{rcl}\text{Efficiency} & = & \dfrac{\text{useful energy out}}{\text{energy in}} \times 100 \,\% \\\\\eta & = & \dfrac{w_{\text{out}}}{w_{\text{in}} } \times 100 \,\%\\\end{array}$

Data:

Useful energy = 3 J

Energy input = 30 J

Calculation:

$\begin{array}{rcl}\eta & = & \dfrac{\text{3 J}}{\text{30 J}} \times 100 \,\%\\\\\eta & = & 10 \, \%\\\end{array}\\\text{ The efficiency is }\boxed{\textbf{10 \%}}$

8 0

3 years ago

Rocks and sand are nonliving .all organisms are

solong [7]

Hey there!

Rocks and sand are nonliving. All organisms are living.
Living organisms have five characteristics. Living organisms respond to a stimulus, need energy, grow, reproduce, and get rid of wastes. All living organisms consist of cells.

Hope this helps! Have a Brainly day! :D

5 0

3 years ago

Which statement best describes a physical change?

yulyashka [42]

The answer is the third one .

7 0

3 years ago

The equilibrium constant Kc for the reaction PCl3(g) + Cl2(g) ⇌ PCl5(g) is 49 at 230°C. If 0.70 mol of PCl3 is added to 0.70 mol

Ymorist [56]

Answer : The correct option is, (B) 0.11 M

Solution :

First we have to calculate the concentration $PCl_3$ and $Cl_2$ .

$\text{Concentration of }PCl_3=\frac{\text{Moles of }PCl_3}{\text{Volume of solution}}$

$\text{Concentration of }PCl_3=\frac{0.70moles}{1.0L}=0.70M$

$\text{Concentration of }Cl_2=\frac{\text{Moles of }Cl_2}{\text{Volume of solution}}$

$\text{Concentration of }Cl_2=\frac{0.70moles}{1.0L}=0.70M$

The given equilibrium reaction is,

$PCl_3(g)+Cl_2(g)\rightleftharpoons PCl_5(g)$

Initially 0.70 0.70 0

At equilibrium (0.70-x) (0.70-x) x

The expression of $K_c$ will be,

$K_c=\frac{[PCl_5]}{[PCl_3][Cl_2]}$

$K_c=\frac{(x)}{(0.70-x)\times (0.70-x)}$

Now put all the given values in the above expression, we get:

$49=\frac{(x)}{(0.70-x)\times (0.70-x)}$

By solving the term x, we get

$x=0.59\text{ and }0.83$

From the values of 'x' we conclude that, x = 0.83 can not more than initial concentration. So, the value of 'x' which is equal to 0.83 is not consider.

Thus, the concentration of $PCl_3$ at equilibrium = (0.70-x) = (0.70-0.59) = 0.11 M

The concentration of $Cl_2$ at equilibrium = (0.70-x) = (0.70-0.59) = 0.11 M

The concentration of $PCl_5$ at equilibrium = x = 0.59 M

Therefore, the concentration of $PCl_3$ at equilibrium is 0.11 M

3 0

3 years ago

3. A helium laser emits light with a wavelength of 6.33 x 10^-7m. What is

HACTEHA [7]

Answer:

4.52 x 10¹⁴ cycles/s

Explanation:

From c = f·λ => f = c/λ = (3.0 x 10⁸ m/s)/(6.63 x 10⁻⁷m) = 4.52 x 10¹⁴ cycles/s.

f = frequency = ?

λ = wavelength = 6.63 x 10⁻⁷ meter

c = speed of light in vacuum = 3.0 x 10⁸ meters/s

7 0

2 years ago