Answer:
P2O3
Explanation:
Firstly, we know that the phosphorus would absorb oxygen from air to form its oxide. We already know the mass of the phosphorus, we can get the mass of the oxygen by subtracting the mass of the phosphorus from the mass of the oxide.
The mass of the oxygen is 2.57 - 1.45 = 1.12g
From here, we covert these masses to moles by dividing by the atomic masses of phosphorus and oxygen respectively.
The atomic mass of phosphorus is 31 while that of oxygen is 16.
P = 1.45/31 = 0.046774193548
O = 1.12/16 = 0.07
We now divide by the smallest which is that of phosphorus.
P = 0.046774193548/ 0.046774193548= 1
O = 0.07/ 0.046774193548 = 1.5
We then multiply the answers by 2 for conversion to whole numbers. Making P = 2 and O = 3
The empirical formula is thus P2O3
Answer:
period 6
Explanation:
If the lanthanides were inserted into the periodic table, they would go into periodic 6.
Their atomic number is between 57 - 71 from element lanthanum to lutetium.
- The elements in this period are 15 in number.
- They are also know as elements in the f-block.
The elements that makes up the series are:
Lanthanum
Cerium
Praseodymium
Neodymium
Promethium
Samarium
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
Lutetium
Answer:
A and D
Explanation:
I took the test, and choose both B and C and got it wrong
Answer:
Threatened Species: A threatened species is a species at risk but not yet endangered. California sea otters were classififed as a threatened species. Laws were passed to protect the otters and now they have increased their population size.
Invasive Species: One of the main causes of extinction and endangered species is the introduction of an exotic species. New exotic species are called invasive species. Invasive species can disrupt food chains, carry disease, prey on native species directly, and out-compete native species for limited resources, like food.
Extinction: If a population decreases too much in numbers, they disappear. Extinct species mean that the species has died out and no individuals left. An example of extinction: New Zealand was once home to a bird called the Giant Moa. Humans settled as their population increased the Moa population decreased. The species is now extinct.
Explanation:
They both turn something on, and the way they are different is the way they turn it off<span>
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