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2 years ago

The period number of any element is equal to the number of its energy levels

Chemistry

1 answer:

gulaghasi [49]2 years ago

7 0

Answer:

The period number refers to the number of electron shells or primary energy levels an atom of each element has. Ex: Period 3 elements—Na, Mg, Al, Si, P, S, Cl, and Ar—have three primary electron energy levels.

true

Explanation:

sorry if wrong pa brainliest nalang :D

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ubstance A undergoes a first order reaction A®B with a half-life, t½, of 20 min at 25 °C. If the initial concentration of A in a

Stells [14]

Answer : The concentration of A after 80 min is, 0.100 M

Explanation :

Half-life = 20 min

First we have to calculate the rate constant, we use the formula :

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{20\text{ min}}$

$k=3.465\times 10^{-2}\text{ min}^{-1}$

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = $3.465\times 10^{-2}\text{ min}^{-1}$

t = time passed by the sample = 80 min

a = initial amount of the reactant = 1.6 M

a - x = amount left after decay process = ?

Now put all the given values in above equation, we get

$80=\frac{2.303}{3.465\times 10^{-2}}\log\frac{1.6}{a-x}$

$a-x=0.100M$

Therefore, the concentration of A after 80 min is, 0.100 M

3 0

2 years ago

Why is it NOT possible for ONE particle (atom/ion/molecule) to be classified as a particular phase, or state, of matter?

Agata [3.3K]

Answer:

because I said and I'm the boss

6 0

2 years ago

Which solution will form a precipitate when mixed with a solution of aqueous na2co3? which solution will form a precipitate when

trapecia [35]

Answer:

$CuCl_{2}(aq.)$ will form a precipitate of insoluble $CuCO_{3}$ when aqueous $Na_{2}CO_{3}$ is added.

Explanation:

According to solubility rule-

all carbonates are insoluble except group IA compounds and $NH_{4}^{+}$

all salts of sodium are soluble

When $Na_{2}CO_{3}$ is added to given solutions, a double displacement reaction takes place in each solution to form a sodium salt and a carbonate salt.

So, in accordance with solubility rule, addition of $Na_{2}CO_{3}$ into $CuCl_{2}(aq.)$ will result precipitation of insoluble $CuCO_{3}$

Reaction: $Na_{2}CO_{3}(aq.)+CuCl_{2}(aq.)\rightarrow 2NaCl(aq.)+CuCO_{3}(aq.)$

4 0

3 years ago

Explain how mendal experiments with seed colors disapproved the common belief of blending inheritance

Elan Coil [88]

The theory of blending inheritance was used to describe an actual blending of our alleles, that together would form a new allele. For example, skin color and height would be the result of the blend of the parent's alleles.
This theory doesn't explain why some traits disapear or are discrete.
On the other hand, Mendel's experiments with seed colors explains it. He demonstrated that genes are inherited in pairs and that in hybrid organisms, dominant versions of that gene, could hide the presence of a recessive version of that same gene.

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3 years ago

When 3.0g of magnesium is burnt in 2.00g of oxygen, 5.00g of magnesium oxide is produced. What mass of magnesium oxide will be f

guajiro [1.7K]

Answer: -

8.00 g

The law of conservation of mass

Explanation: -

When magnesium burns in air it combines with oxygen to form magnesium oxide.

The mass of the product is the mass of the magnesium oxide.

The mass of the reactant is the mass of the magnesium + mass of the oxygen.

Since matter cannot be created or destroyed according to the law of conservation of mass,

Mass of Magnesium oxide formed = mass of magnesium reacted + mass of oxygen reacted

= 3.00 g + 5.00 g

= 8.00 g

3 0

2 years ago