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3 years ago

How many groups and periods are present in the periodic table?

Chemistry

2 answers:

PilotLPTM [1.2K]3 years ago

7 0

Answer:

Explanation:

There are seven periods in the periodic table, with each one beginning at the far left. A new period begins when a new principal energy level begins filling with electrons. Period 1 has only two elements (hydrogen and helium), while periods 2 and 3 have 8 elements. Periods 4 and 5 have 18 elements.

Elenna [48]3 years ago

6 0

Answer:

<h2>18 groups</h2>

In the periodic table, there are 7 periods and 18 groups.

Explanation:

#CARRY ON LEARNING

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Ann [662]

Answer: The coefficients are 2, 2 and 1.

Explanation: According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants.

The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

The balanced chemical equation for the given reaction is:

2H2o➡️2h2+o2

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3 years ago

A. What is the chemical reaction between hydrogen and sulfur?

DanielleElmas [232]

Answer & Explanation:

At high temperatures or in the presence of catalysts, sulfur dioxide reacts with hydrogen sulfide to form elemental sulfur and water. This reaction is exploited in the Claus process, an important industrial method to dispose of hydrogen sulfide.

6 0

3 years ago

An exponent of "2" means that if we double the concentration of the reactant the rate doubles as well Exponents in rate laws are

Karo-lina-s [1.5K]

Answer:

- False.

- True.

Explanation:

Hello, for each statement we state:

- An exponent of "2" means that if we double the concentration of the reactant the rate doubles as well.

FALSE because considering a rate law like:

$-r=kC^2$

The exponent of "2" powers the concentration to the second power, not doubles the rate law, thus, if C is 3, for k=1, r will be -9. On the other hand if the rate is like:

$-r=kC$

The rate will be -3, that is why the rate is not doubled when the "2" in concentration is present.

- Exponents in rate laws are based on the coefficients from the balanced equation.

FALSE because for nonelemental chemical reactions, the exponents do not match with each species' stoichiometric coefficients in the rate law.

- The rate constant, k, takes into account the effect of activation energy and temperature on the reaction.

TRUE, since the Arrhenius equation allows us to prove the effect of the activation energy and the temperature:

$k=Aexp(-\frac{Ea}{RT})$

- Differential rate laws allow us to compare concentration and time.

TRUE as they are given like:

$\frac{1}{\nu _A} \frac{dC_A}{dt} =\frac{1}{\nu _B} \frac{dC_B}{dt} =...$

Best regards.

5 0

3 years ago

If a 12-volt battery produces a current of 20 amps, what is the resistance?

mixas84 [53]

Answer:

0.6 Ω

Explanation:

From the question given above, the following data were obtained:

Voltage (V) = 12 V

Current (I) = 20 A

Resistance (R) =?

From Ohm's law,

V = IR

Where:

V => is the voltage

I => is the current

R => R is the resistance

With the above formula, we can obtain the resistance as follow:

Voltage (V) = 12 V

Current (I) = 20 A

Resistance (R) =?

V = IR

12 = 20 × R

Divide both side by 20

R = 12 / 20

R = 0.6 Ω

Thus the resistance is 0.6 Ω

4 0

3 years ago

Nitrogen-13 has a half-life of about 10 minutes. How much of a 320g sample of N-13 would remain after 40 minutes?

lubasha [3.4K]

Answer:

The half-life of a radioisotope describes the amount of time it takes for said isotope to decay to one-half the original amount present in the sample.

Nitrogen-13, because it has a half-life of ten minutes, will experience two half-lives over the course of the twenty minute period. This means that 25% of the isotope will remain after this.

0.25 x 128mg = 32mg

32mg of Nitrogen-13 will remain after 20 minutes.

5 0

3 years ago

How many groups and periods are present in the periodic table?​

How many groups and periods are present in the periodic table?