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3 years ago

Why are atomic masses on the Periodic Table written in decimals when they are based on mass numbers that can be whole numbers?

1 answer:

8 0

To allow for equations and problems in chemistry to be as precise as possible. When experiments are conducted, and even if the number is the slightest bit off, the problem or experiment could be impacted very negatively. It allows for complete accuracy to ensure nothing goes wrong, since chemistry is very touchy and risky when dealing with extremely unsafe elements.

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20 Points and will mark as brainliest if explained

Sergeu [11.5K]

Answer:

I think 4 but i can't explain how but use the info i know

Explanation:

The electron configuration of an atomic species (neutral or ionic) allows us to understand the shape and energy of its electrons. Many general rules are taken into consideration when assigning the "location" of the electron to its prospective energy state, however these assignments are arbitrary and it is always uncertain as to which electron is being described. Knowing the electron configuration of a species gives us a better understanding of its bonding ability, magnetism and other chemical properties.

3 0

3 years ago

How many miles of iron can be produced from 3.5 moles of Fe2O3 and 6.2 moles of CO

AlekseyPX

Answer:

4.13 moles of Fe.

Explanation:

Given data:

Moles of iron produced = ?

Moles of Fe₂O₃ = 3.5 mol

Moles of CO = 6.2 mol

Solution:

Chemical equation:

Fe₂O₃ + 3CO → 2Fe + 3CO₂

Now we will compare the moles of iron with CO and Fe₂O₃.

Fe₂O₃ : Fe

1 : 2

3.5 : 2/1×3.5 = 7 mol

CO : Fe

3 : 2

6.2 : 2/3×6.2 = 4.13 mol

The number of moles of iron produced by CO are less it will limiting reactant.

Thus, moles of iron formed in given reaction are 4.13 moles.

6 0

3 years ago

How many chlorine aHow many chlorine atoms are there in 4 molecules of CH2Cl2?

timurjin [86]

If there is 4 of CH2CI2, then there is 8 of CI. There is already 2 in each one and there is 4 sets so 2x4=8

8 0

3 years ago

2.2. Name the two stages of photosynthesis

andre [41]

Answer:

1. Light-dependent stage

2. Light-independent stage or Calvin cycle

Explanation:

Photosynthesis is the process by which plants and other autotrophic organisms synthesize their food (glucose) in the presence of sunlight as energy source. However, this photosynthetic process, which is a metabolic reaction occurs in two stages namely; Light-dependent stage and Light-independent stage.

- The light dependent stage occurs in the thylakoid membrane of the chloroplast. It involves the synthesis of NADPH and ATP needed for the light independent stage of photosynthesis.

- The light independent stage also known as Calvin cycle occurs in the stroma of the chloroplast. This is the stage where glucose is synthesized using inorganic source of carbon (CO2).

6 0

4 years ago

What fraction of a Sr-90 sample remains unchanged after 87.3 years

jolli1 [7]

The answer is 1/8.

Half-life is the time required for the amount of a sample to half its value.
To calculate this, we will use the following formulas:
1. $(1/2)^{n} = x$ ,
where:
n - a number of half-lives
x - a remained fraction of a sample

2. $t_{1/2} = \frac{t}{n}$
where:
 $t_{1/2}$ - half-life
t - total time elapsed
n - a number of half-lives

The half-life of Sr-90 is 28.8 years.
So, we know:
t = 87.3 years
 $t_{1/2}$ = 28.8 years

We need:
n = ?
x = ?

We could first use the second equation, to calculate n:
If:
$t_{1/2} = \frac{t}{n}$ ,
Then:
$n = \frac{t}{ t_{1/2} }$
⇒ $n = \frac{87.3 years}{28.8 years}$
⇒ $n=3.03$
⇒ n ≈ 3

Now we can use the first equation to calculate the remained amount of the sample.
 $(1/2)^{n} = x$
⇒ $x=(1/2)^3$
⇒ $x= \frac{1}{8}$

8 0

4 years ago