CHEMISTRY HIGH SCHOOL

The first person to develop the periodic table was _____. Mendeleev Dalton Bohr Rutherford

Answers

Answer 1

Answer: Mendeleev was the first.

Answer 2

Answer:

Answer:

Mendeleev was the first to develop the periodic table

Explanation:

Related Questions

What is the difference between a period and a group on the periodic table
According to modern atomic theory, the exact location of a(n) ____________________ is uncertain.
A similarity between the forces involved in both ionic and covalent bondingis that bothO A) involve the sharing of electrons.O B) involve the transfer of electrons.O C) involve the attraction of opposite charges.requre same amountof energy toereakther bonds
An electron has a charge identical to that of
How would you be able to use the spectrum of each gas to establish its identity

What element forms a compound with chlorine with the general formula MCl?

Answers

Rb forms a c ok compound with the general formula MCI.

Rubidium forms a compound with chlorine and has the general formula MCl

If it takes 54 mL of 0.1 M NaOH to neutralize 125 mL of an HCl solution,what is the concentration of the HCl ?

Answers

volume of NaOH = 54 mL / 1000 = 0.054 L

Molarity NaOH = 0.1 M

Number of moles NaOH :

n = M * v

n = 0.1 * 0.054

n = 0.0054 moles of NaOH

Finally we calculate the number of moles of HCl in the solution from the stoichiometry of the reaction :

HCl + NaOH = NaCl + H₂O

1 mole HCl -------- 1 mole NaOH
? moles HCl ------- 0.0054 moles NaOH

moles HCl = 0.0054 * 1 /1

= 0.0054 moles of HCl

Volume of HCl = 125 mL / 1000 = 0.125 L

M ( HCl ) = n / V

M = 0.0054 / 0.125

= 0.0432 M

hope this helps!

Find the [H+] in an acetic acid solution that has a pH of 5.12

Answers

Data:
pH = 5.2
[H+] = ?

Knowing that: (Equation to find the pH of a solution)
$pH = -log[H+]$

Solving:
$pH = -log[H+]$
$5.2 = - log [H+]$
Knowing that the exponential is the opposite operation of the logarithm, then we have:
$[H+] = 10^(-5.2)$
$\boxed{\boxed{[H+] = 6.30*10^(-6)}}\end{array}}\qquad\quad\checkmark$

Calculate the ph and poh of a 0.0032 M solution of nitric acid NHO3

Answers

Answer:

HNO3 ->NO3²- + H+

Concentration of H+ ions= 0.0032M

pH = - log[ H+]

= - log (0.0032)

= 2.49

pH + pOH = 14

pOH = 14 - pH

= 14 - 2.49

= 11.51

pH = 2.49 and pOH = 11.51

Hope this helps.

Use Hess's law and the following equations to calculate the ΔHreaction for the reaction CO(g) + 3H2(g) CH4(g) + H2O(g). (Show your work.) (4 points) • C(s) + O2(g) CO(g) ΔH = –110.5 kJ • C(s) + 2H2(g) CH4(g) ΔH = –74.85 kJ • H2(g) + O2(g) H2O(g) ΔH = –241.83 kJ

Answers

Answer: The enthalpy of reaction is, -206.18 kJ

Explanation:-

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The final reaction is

$CO(g)+3H_2(g)\rightarrow CH_4(g)+H_2O(g)$ $\Delta H_(rxn)=?$

The intermediate balanced chemical reaction will be,

(1) $C(s)+(1)/(2)O_2(g)\rightarrow CO(g)$ $\Delta H_1=-110.5kJ$

(2) $C(s)+2H_2(g)\rightarrow CH_4(g)$ $\Delta H_2=-74.85kJ$

(3) $H_2(g)+(1)/(2)O_2(g)\rightarrow H_2O(g)$ $\Delta H_3=-241.83kJ$

Now adding (2) and (3) and subtracting (1) , we get :

$\Delta H_(rxn)=(\Delta H_2+\Delta H_3)-\Delta H_1$

$\Delta H_(rxn)=((-74.85)+(-241.83))-(-110.5)$

$\Delta H_(rxn)=-206.18kJ$

Therefore, the enthalpy of reaction is, -206.18 kJ

Final answer:

To calculate the ΔHreaction for the given reaction using Hess's Law, we need to manipulate the given equations and sum up the ΔH values. After manipulating the equations and summing up the ΔH values, the ΔHreaction is -280.03 kJ.

Explanation:

To calculate the ΔHreaction for the given reaction, we can use Hess's Law. We need to manipulate the given equations to match the overall reaction. Since the overall reaction involves CO, H2, CH4, and H2O, we can use the given equations as follows:

Reverse the equation for CO(g) + O2(g) → CO(g) to get CO(g) → C(s) + O2(g).
Double the equation for C(s) + 2H2(g) → CH4(g) to get 2C(s) + 4H2(g) → 2CH4(g).
Leave the equation for H2(g) + O2(g) → H2O(g) as is.

Add up the manipulated equations and their respective ΔH values:

CO(g) → C(s) + O2(g) (ΔH = 110.5 kJ)
2C(s) + 4H2(g) → 2CH4(g) (ΔH = -2 * 74.85 kJ = -149.7 kJ)
H2(g) + O2(g) → H2O(g) (ΔH = -241.83 kJ)

Now, sum up the ΔH values:

110.5 kJ + (-149.7 kJ) + (-241.83 kJ) = -280.03 kJ

Therefore, the ΔHreaction for the reaction CO(g) + 3H2(g) → CH4(g) + H2O(g) is -280.03 kJ.

Learn more about Hess's Law here:

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If an atom has 35 protons in the nucleus, how many will it have orbiting nucleus

Answers

It will have 35 ''electrons'' . Basically the number of protons in the nucleus of an atom is always equal to the number of electrons but its just that protons are positively charged and electrons are negatively charged.

Final answer:

An atom is electrically neutral when it has an equivalent number of protons and electrons. Therefore, an atom with 35 protons in the nucleus will also have 35 electrons orbiting the nucleus.

Explanation:

In atomic theory, an atom is neutral when the number of protons present in the nucleus is equal to the number of electrons orbiting the nucleus. For example, hydrogen atoms all have one proton in the nucleus and one electron orbiting the nucleus. Therefore, if an atom has 35 protons in the nucleus, it will also have 35 electrons orbiting the nucleus. This is due to the characteristic of atomic structure that aims for neutrality by maintaining an equal number of positive protons and negative electrons.

Learn more about Atomic Structure here:

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Describe the general location of the electrons in a covalent bond

All of the following are part of the digestive system except the __________.Select one of the options below as your answer:a. stomachb. esophagusc. intestinesd. heart

What is the theoretical yield of aluminum that can be produced by the reaction of 60.0 g of aluminum oxide with 30.0 g of carbon according to the following chemical equation? Al2O3 + 3C → 2Al + 3CO