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Alla [95]
4 years ago
9

These four ELEMENTS were found in early earth and they make up all living things.

Chemistry
2 answers:
Bogdan [553]4 years ago
7 0
Its is A. true ($:!:!:!:!::!/!!2!2$2$2$:$!:!.!.!.!.!:!!..!!:!:!:!:!:!:!!:!:!:!:!)))
VladimirAG [237]4 years ago
6 0

Answer: True

Air is a mixture of many things; it's not just Oxygen, but Hydrogen, Carbon, and Nitrogen as well are made up of air. Fun fact: Nitrogen is actually more abundant in air

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SOMEONE HELP ME PLEASE ILL GIVE BRAINLY
Maksim231197 [3]

Answer:

true

Explanation:

just did it

6 0
3 years ago
A pan containing 20.0 grams of water was allowed to cool from a temperature of 95.0 °C. If the amount of heat released is 1,200
Sedbober [7]

Answer:

81°C.

Explanation:

To solve this problem, we can use the relation:

<em>Q = m.c.ΔT,</em>

where, Q is the amount of heat released from water (Q = - 1200 J).

m is the mass of the water (m = 20.0 g).

c is the specific heat capacity of water (c of water = 4.186 J/g.°C).

ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = final T - 95.0°C).

∵ Q = m.c.ΔT

∴ (- 1200 J) = (20.0 g)(4.186 J/g.°C)(final T - 95.0°C ).

(- 1200 J) = 83.72 final T - 7953.

∴ final T = (- 1200 J + 7953)/83.72 = 80.67°C ≅ 81.0°C.

<em>So, the right choice is: 81°C.</em>

7 0
4 years ago
How is shielding effect related to atomic radius?
jolli1 [7]
Shielding effect being attendency of the inner electrons to repel the outermost electrons, an increase in shielding effect increases atomic radius and decrease reduces the atomic radius
7 0
3 years ago
The reaction of Fe₂O₃ with CO produces Fe(s) and CO₂(g). What mass of Fe₂O₃ is required to produce 5.00 kg of Fe(s) if the perce
irina [24]

Answer:

2.75g

Explanation:

Firstly, we write a balanced equation of the reaction.

Fe2O3(s)+3CO(g)-->2Fe(s)+3CO2(g).

Now, we write the formula for the percentage yield.

Percentage yield = Actual yield/theoretical yield * 100%

From the equation, we can see that we have one unknown

We convert the 5kg to g. It must be known that 5kg is 5000g as 1kg equals 1000g.

Now, we are asked to calculate the mass of the iron iii oxide required.

From the balanced equation we can see that 1 mole of iron trioxide yielded 2 moles of Fe.

Now, let’s calculate the mass required. We calculate the actual number of moles of iron produced. This is the mass of iron divided by the molar mass. The atomic mass of iron is 56 amu. The number of moles of iron produced is 5000/56 moles

Since the mole ratio is 1 to 2, the number of moles of iron trioxide thus used is 5000/56 divided by 2 which equals 5000/112 moles.

Now, we proceed to calculate the mass of iron trioxide used. The mass is equal the molar mass multiplied by the number of moles. The molar mass of iron trioxide is 2(56) + 3(16) = 112 + 48 = 160g/mol

The mass thus required to produce 5kg of iron is 5000/112 * 160 which is 3,500g or 3.5kg. We know this to be the theoretical mass, the actual mass is calculated using the formula given above.

78.5 = actual mass/3.5 * 100

Actual mass = (3.5 * 78.5) /100

= 2.75g

6 0
3 years ago
Simplify the ratio 32:21 in its simplest form ..show your working​
makvit [3.9K]

Answer:

32/21

Explanation:

Find the GCD (or HCF) of numerator and denominator. GCD of 32 and 21 is 1.

32 ÷ 121 ÷ 1.

Reduced fraction: 3221. Therefore, 32/21 simplified to lowest terms is 32/21.

8 0
3 years ago
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