All categories

3 years ago

The information below is a description of a substance:

Chemistry

1 answer:

skelet666 [1.2K]3 years ago

7 0

Answer:

A chemical change

Explanation:

You might be interested in

Different elements emit different emission spectra when they are excited because each type of element has a unique energy level

jonny [76]

Different elements emit different spectra when their electrons get excited because each element has a different arrangement of electrons surrounding the nucleus. The energy levels in which the electrons can occupy are unique to a specific element. When an electron gets excited into a higher energy level, it will eventually relax back into its original state and emit light corresponding to that energy.

8 0

3 years ago

over a 12.3 minuete period 5.13 E-3 moles of F2 gas effuses from a contaier. How many moles of CH4 gas could effuse from from th

Aleonysh [2.5K]

Answer : The moles of methane gas could be, $7.90\times 10^{-3}mol$

Solution :

According to the Graham's law, the rate of effusion of gas is inversely proportional to the square root of the molar mass of gas.

$R\propto \sqrt{\frac{1}{M}}$

or,

$(\frac{R_1}{R_2})=\sqrt{\frac{M_2}{M_1}}$

$[\frac{(\frac{n_1}{t_1})}{(\frac{n_2}{t_2})}]=\sqrt{\frac{M_2}{M_1}}$

where,

$R_1$ = rate of effusion of fluorine gas

$R_2$ = rate of effusion of methane gas

$n_1$ = moles of fluorine gas = $5.13\times 10^{-3}mol$

$n_2$ = moles of methane gas = ?

$t_1=t_2$ = time = 12.3 min (as per question)

$M_1$ = molar mass of fluorine gas = 38 g/mole

$M_2$ = molar mass of methane gas = 16 g/mole

Now put all the given values in the above formula 1, we get:

$[\frac{(\frac{5.13\times 10^{-3}mol}{12.3min})}{(\frac{n_2}{12.3min})}]=\sqrt{\frac{16g/mole}{38g/mole}}$

$n_2=7.90\times 10^{-3}mol$

Therefore, the moles of methane gas could be, $7.90\times 10^{-3}mol$

8 0

3 years ago

If element X has 59 protons, how many electrons does it have?

laiz [17]

If element X has 59 protons then element X has 59 electrons.

Side note: as long as an element stays an atom the number of protons and electrons will always have the same value.

8 0

3 years ago

A Metal mass of 71.68g occupies a volume of 8cm^3. Calculate the density

Damm [24]

Density = mass
--------------
volume

= 71.68
-------------
8

= 8.96 g/cm3.

Hope this helps!

5 0

4 years ago

If you start with 100 grams of hydrogen-3, how many grams will you have after 24.6 years?

svet-max [94.6K]

Answer:

The mass left after 24.6 years is 25.0563 grams

Explanation:

The given parameters are;

The mass of the hydrogen-3 = 100 grams

The half life of hydrogen-3 which is also known as = 12.32 years

The formula for calculating half-life is given as follows;

$N(t) = N_0 \times \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{\frac{1}{2} }} }$

Where;

N(t) = The mass left after t years

N₀ = The initial mass of the hydrogen-3 = 100 g

t = Time duration of the decay = 24.6 years

$t_{\frac{1}{2} }$ = Half-life = 12.32 years

$N(24.6) = 100 \times \left (\dfrac{1}{2} \right )^{\dfrac{24.6}{12.32}} } = 25.0563$

The mass left after 24.6 years = 25.0563 grams.

4 0

3 years ago