Answer:
the correct answer is four decimal places
The correct answer is D.
Echo refers to the sound that is heard when a sound wave is reflected back from a surface. An echo sound is made when a sound wave traveled through the air, hit a hard surface and get reflected back. Generally, hard surfaces reflect sound wave while soft surfaces absorb sound waves. Reflected sound waves are used in application of some devices that are used in range and direction finding.
Answer:
4.43 g of Oxygen
Explanation:
As shown in Chemical Formula, one mole of Aluminium Sulfate [Al₂(SO₄)₃] contains;
2 Moles of Aluminium
3 Moles of Sulfur
12 Moles of Oxygen
Also, the Molar Mass of Aluminium Sulfate is 342.15 g/mol. It means,
342.15 g ( 1 mole) of Al₂(SO₄)₃ contains = 192 g (12 mole) of O
So,
7.9 g of Al₂(SO₄)₃ will contain = X g of O
Solving for X,
X = (7.9 g × 192 g) ÷ 342.15 g
X = 4.43 g of Oxygen
Because they are coming from the ground and always safe
