Ask question

Ask question

All categories

2 years ago

13

pure substance x is a green powder. when heated, it gives off a gas and changes to a black powder. is substance x an element or

a compound? give reasons

1 answer:

gogolik [260]2 years ago

7 0

I'd say it is an element. It is not a compound, it doesn't do things on its own like us. It's an element like fire and water.

You might be interested in

What happens when chlorine from<br> CFCs mixes with ozone?

Svetach [21]

Answer:

Because they are extremely stable molecules, CFCs do not react easily with other chemicals in the lower atmosphere. ... Free chlorine atoms then react with ozone molecules, taking one oxygen atom to form chlorine monoxide and leaving an ordinary oxygen molecule.

Explanation:

5 0

2 years ago

c3H8 + 5O2 = 3CO2 + 4H2O When 44.0 grams of propane (C3H8) under goes complete combustion, how many grams of water will be produ

Umnica [9.8K]

<u>Answer:</u> 72 grams of water will be produced.

<u>Explanation:</u>

To calculate the number of moles, we use the formula:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ....(1)

Mass of propane = 44 grams

Molar mass of propane = 44 grams

Putting values in above equation, we get:

$\text{moles of propane}=\frac{44g}{44g/mol}=1mole$

For the reaction of combustion reaction of propane, the equation follows:

$C_3H_8+5O_2\rightarrow 3CO_2+4H_2O$

By Stoichiometry of the reaction,

1 mole of propane produces 4 moles of water.

So, 1 mole of propane will produce = $\frac{1}{1}\times 4=4moles$ of water.

Now, to calculate the amount of water, we use equation 1, we get:

Molar mass of water = 18 g/mol

$4mol=\frac{\text{Mass of water}}{18g/mol}$

Mass of water produced = 72 grams

Hence, 72 grams of water will be produced.

6 0

3 years ago

The universe is made up of ____

vladimir2022 [97]

The correct should be A. thousands of galaxies

7 0

2 years ago

Read 2 more answers

A solution with a pH = 13 has approximately how many moles of OH– ions per liter?

GuDViN [60]

Answer :

(A) The number of moles of $OH^-$ ions per liter is, 0.1 moles/L

(B) The number of molecules of $H^+$ ion is, $6.022\times 10^{10}$

(C) The pH of the solution will be, 4

<u>Solution for part A :</u>

First we have to calculate the pOH of the solution.

As we know that,

$pH+pOH=14\\\\13+pOH=14\\\\pOH=1$

Now we have to calculate the moles of $OH^-$ ion per liter.

$pOH=-\log [OH^-]\\\\1=-\log [OH^-]$

$[OH^-]=0.1moles/L$

<u>Solution for part B :</u>

First we have to calculate the $H^+$ ion concentration.

$pH=-\log [H^+]\\\\13=-\log [H^+]$

$[H^+]=10^{-13}moles/L$

Now we have to calculate the number of molecules of $H^+$ ion

As, 1 mole contains $6.022\times 10^{23}$ number of molecules of $H^+$ ion

So, $10^{-13}$ moles contains $6.022\times 10^{23}\times 10^{-13}=6.022\times 10^{10}$ number of molecules of $H^+$ ion

<u>Solution for part C :</u>

$pH=-\log [H^+]\\\\pH=-\log (1\times 10^{-4})$

$pH=4$

6 0

3 years ago

Read 2 more answers

1. What is the flame color of sodium?<br> yellow-orange<br> purple<br> green<br> blue-green

juin [17]

Orange is the color of Sodium

4 0

2 years ago