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2 years ago

Where are elements with atomic numbers 1 and 2?

Chemistry

2 answers:

Maru [420]2 years ago

5 0

Answer:hydrogen(H) is 1 and helium(He) is 2

hydrogen is a nonmetal and helium is a nobel gas. hydrogen is found in group S and helium is found in group P

Explanation:hope this helps

rusak2 [61]2 years ago

5 0

Answer:

1 H Hydrogen 1.00797

2 He Helium 4.00260

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CH3COOH mc015-1.jpg CH3COO– (aq) + H+(aq) What will happen to the chemical equilibrium of the solution if CH3COONa is added?

andrey2020 [161]

The equilibrium will shift to the left or the backward reaction since addition of CH3COONa will add more CH3COO- ions to the solution. The formation of reactants are promoted.

7 0

3 years ago

Suppose a new group 5A element is discovered. Photoelectron spectroscopy (PES) reveals that its last two peaks occur at 1370 kJ/

iren2701 [21]

Answer: The average valence electron energy (AVEE) of this element =

1014.2 KJ/ mol or 1.0142mJ/mol.

Explanation:

The average valence electron energy = (number of electrons in s subshell x Ionization energy of that subshell) + (number of electrons in p subshell x Ionization energy of that subshell) / total number of electrons in both subshells of the valence shells.

The 5A elements are non-metals like Nitrogen and Phosphorus with the metallic character increasing as you go down the group, So a new 5A element will have characteristics of its group with 5 valence electron in its outermost shell represented as ns2 np3

Therefore the average valence electron energy (AVEE) of this element will be calculated as

The average valence electron energy = (2 x 1370 kJ/mol + 3 x 777 kJ/mol.) / 5

2740+2331/ 5 =5071/5

=1014.2 KJ/ mol or 1.0142mJ/mol.

5 0

3 years ago

What is the gram formula mass of Ca3(PO4)2

Georgia [21]

Mass Molar of $Ca_{3} (PO_4)_2$
Ca = 3*40 = 120 amu
P = 2*31= 62 amu
O = (16*4)*2 = 64*2 = 128 amu
--------------------------------------
Mass Molar of $Ca_{3} (PO_4)_2$ = 120 + 62 + 128 = 310 g/mol

Therefore: What is the gram formula mass of Ca3(PO4)2 ?
Answer: 310 grams

6 0

3 years ago

which two will help you measure how different colors absorb the energy in sunlight is it beaker or thermometer

KATRIN_1 [288]

Beaker does thermometer measures the thermal energy in the air

6 0

3 years ago

Calculate the standard enthalpy change for the reaction at 25 ∘ 25 ∘ C. Standard enthalpy of formation values can be found in th

WINSTONCH [101]

Answer: The standard enthalpy change of the reaction is coming out to be -16.3 kJ

Explanation:

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. It is represented as $\Delta H$

The equation used to calculate enthalpy change is of a reaction is:

$\Delta H_{rxn}=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]$

For the given chemical reaction:

$Mg(OH)_2(s)+2HCl(g)\rightarrow MgCl_2(s)+2H_2O(g)$

The equation for the enthalpy change of the above reaction is:

$\Delta H_{rxn}=[(1\times \Delta H_f_{(MgCl_2(s))})+(2\times \Delta H_f_{(H_2O(g))})]-[(1\times \Delta H_f_{(Mg(OH)_2(s))})+(2\times \Delta H_f_{(HCl(g))})]$

We are given:

$\Delta H_f_{(Mg(OH)_2(s))}=-924.5kJ/mol\\\Delta H_f_{(HCl(g))}=-92.30kJ/mol\\\Delta H_f_{(MgCl_2(s))}=-641.8kJ/mol\\\Delta H_f_{(H_2O(g))}=-241.8kJ/mol$

Putting values in above equation, we get:

$\Delta H_{rxn}=[(1\times (-641.8))+(2\times (-241.8))]-[(1\times (-924.5))+(2\times (-92.30))]\\\\\Delta H_{rxn}=-16.3kJ$

Hence, the standard enthalpy change of the reaction is coming out to be -16.3 kJ

6 0

3 years ago