Neon, Helium, Krypton, Xenon, Argon
Answer:
a) 0,5
Explanation:
If x=6 and y=2, then (2x-4y)/(x+y)=(2*6-4*2)/(6+2)=(12-8)/8=4/8= 0,5
The black lines in the Sun's spectrum are caused by gases on, or above, the Sun's surface that absorb some of the emitted light.
Answer:approx 300,000 years ago
Explanation:
Fossils attributed to H. sapiens, along with stone tools, dated to approximately 300,000 years ago, found at Jebel Irhoud, Morocco yield the earliest fossil evidence for anatomically modern Homo sapiens
1) State the balanced chemical equation
Na3 PO4 + 3 AgNO3 → 3NaNO3 + Ag3 PO4
sodium phosphate silver nitrate sodium nitrate silver phosphate
2) State the molar ratios
1 mol Na3PO4 : 3 mol AgNO3 : 3 mol NaNO3 : 1 mol Ag3 PO4
3) As you see 3 moles of Silver Nitrate react with 1 mol of Na3 PO4, then you will need.
The you need to use the molar ratio 1:3 to calculate the number of moles of sodium phosphate
1 mol Ag NO3 * [ 1 mol Na3 PO4 / 3 mol Ag NO3] = 0.33 mol Na3 PO4
Answer: 0.33 mol sodium phosphate
