<u>Answer:</u> The density of substance is 
<u>Explanation:</u>
To calculate density of a substance, we use the equation:

We are given:
Mass of substance = 61.6 g
Volume of substance = 
Putting values in above equation, we get:

Hence, the density of substance is 
a minute planet; a body that could or did come together with many others under gravitation to form a planet. Planetesimals are small rock fragments that combined together to eventually form planets
To give 33.6 dm³ hydrogen gas at STP, 18.06 x 10²³ atoms of Na must react completely.
<h3>What is Mole concept ?</h3>
A mole is a unit of measurement used to measure the amount of any fundamental entity (atoms, molecules, ions) present in the substance.
As according to the given equation, 2 moles (ie 12.04 x 10²³ atoms) of Na-atoms produces 1 mole (22.4 ltr) of H₂-gas.
Hence, to produce 33.6 ltr (equivalent to 33.6 dm³) of H₂-gas produced by ;
= 12.04 x 10²³ atoms of Na / 22.4 ltr of H₂-gas x 33.6 ltr
= 18.06 x 10²³ atoms of Na
Hence, To give 33.6 dm³ hydrogen gas at STP, 18.06 x 10²³ atoms of Na must react completely.
Learn more about Mole concept here ;
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Use Boyle's Law of Pressure: P1 x V1 = P2 x V2. Givens: P1=0.9 atm V1= 4 P2= 0.9 atm Find: V2 Equation: 0.9 atm x 4 x 4 L = 0.20 atm x V2Solve: 36 atmL= 0.20 atm x V2 18 : = V2 Short answer: The new volume is 104 ml.
Hey there!
Sulphur is the element which has 6 electrons in the outermost shell.
WhereasCalcium,Neon have 2 and chlorine has 7.
Hope this explanation helps you :)
Have a good day :)