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3 years ago

How did aristotles idea of matter differ from that of scientists

1 answer:

monitta3 years ago

4 0

Aristotle was an ancient Greek philosopher who believed that matter was made up of four main elements. The elements were: air, earth, wind, or fire. He also believed that matter was a compound of either hot and cold or wet and dry.

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Write electron configurations for Gallium, Ga (Z=31), and show the total valence electrons

ivann1987 [24]

Answer: The electronic configuration of gallium is written below and number of valence electrons is 3.

Explanation:

Electronic configuration is defined as the representation of electrons around the nucleus of an atom.

Number of electrons in an atom is determined by the atomic number of that atom.

Valence electrons are defined as the electrons present in the outermost shell of an atom.

We are given:

An element Gallium having atomic number as 31.

Number of electrons = 31

Electronic configuration of Gallium is: $(Z=31):1s^22s^22p^63s^23p^64s^23d^{10}4p^1$

This element has 3 electrons in its outermost shell. So, the number of valence electrons is 3

Hence, the electronic configuration of gallium is written below and number of valence electrons is 3.

3 0

3 years ago

The morning temperature in a city is 41°F. If a sunny, mild day is forecast, which temperature is most likely for 2:00 p.m.?

romanna [79]

Answer:

huh

Explanation:

5 0

2 years ago

A sample of phosphonitrilic bromide, PNBr2, contains 2.01 mol of the compound. Determine the amount (in mol) of each element pre

nordsb [41]

Answer:

2.01 moles of P → 1.21×10²⁴ atoms

2.01 moles of N → 1.21×10²⁴ atoms

4.02 moles of Br → 2.42×10²⁴ atoms

Explanation:

We begin from this relation:

1 mol of PNBr₂ has 1 mol of P, 1 mol of N and 2 moles of Br

Then 2.01 moles of PNBr₂ will have:

2.01 moles of P

2.01 moles of N

4.02 moles of Br

To determine the number of atoms, we use the relation:

1 mol has NA (6.02×10²³) atoms

Then: 2.01 moles of P will have (2.01 . NA) = 1.21×10²⁴ atoms

2.01 moles of N (2.01 . NA) = 1.21×10²⁴ atoms

4.02 moles of Br (4.02 . NA) = 2.42×10²⁴ atoms

6 0

3 years ago

Read 2 more answers

Sulfuryl dichloride is formed when sulfur dioxide reacts with chlorine.

zubka84 [21]

Answer: The value of $\Delta G^o$ of the reaction is 28.38 kJ/mol

Explanation:

For the given chemical reaction:

$SO_2(g)+Cl_2(g)\rightarrow SO_2Cl_2(g)$

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

$\Delta H^o_{rxn}=\sum [n\times \Delta H^o_f_{(product)}]-\sum [n\times \Delta H^o_f_{(reactant)}]$

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

$\Delta H^o_{rxn}=[(1\times \Delta H^o_f_{(SO_2Cl_2(g))})]-[(1\times \Delta H^o_f_{(SO_2(g))})+(1\times \Delta H^o_f_{(Cl_2(g))})]$

We are given:

$\Delta H^o_f_{(SO_2Cl_2(g))}=-364kJ/mol\\\Delta H^o_f_{(SO_2(g))}=-296.8kJ/mol\\\Delta H^o_f_{(Cl_2(g))}=0kJ/mol$

Putting values in above equation, we get:

$\Delta H^o_{rxn}=[(1\times (-364))]-[(1\times (-296.8))+(1\times 0)]=-67.2kJ/mol=-67200J/mol$

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

$\Delta S^o_{rxn}=\sum [n\times \Delta S^o_f_{(product)}]-\sum [n\times \Delta S^o_f_{(reactant)}]$

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

$\Delta S^o_{rxn}=[(1\times \Delta S^o_{(SO_2Cl_2(g))})]-[(1\times \Delta S^o_{(SO_2(g))})+(1\times \Delta S^o_{(Cl_2(g))})]$

We are given:

$\Delta S^o_{(SO_2Cl_2(g))}=311.9J/Kmol\\\Delta S^o_{(SO_2(g))}=248.2J/Kmol\\\Delta S^o_{(Cl_2(g))}=223.0J/Kmol$

Putting values in above equation, we get:

$\Delta S^o_{rxn}=[(1\times 311.9)]-[(1\times 248.2)+(1\times 223.0)]=-159.3J/Kmol$

To calculate the standard Gibbs's free energy of the reaction, we use the equation:

$\Delta G^o_{rxn}=\Delta H^o_{rxn}-T\Delta S^o_{rxn}$

where,

$\Delta H^o_{rxn}$ = standard enthalpy change of the reaction =-67200 J/mol

$\Delta S^o_{rxn}$ = standard entropy change of the reaction =-159.3 J/Kmol

Temperature of the reaction = 600 K

Putting values in above equation, we get:

$\Delta G^o_{rxn}=-67200-(600\times (-159.3))\\\\\Delta G^o_{rxn}=28380J/mol=28.38kJ/mol$

Hence, the value of $\Delta G^o$ of the reaction is 28.38 kJ/mol

7 0

3 years ago

Which statements about oxygen and nitrogen are true? Select all the correct answers. a. They are both normally found as gases in

allsm [11]

a. They are both normally found as gases in the atmosphere. TRUE

That is correct, the oxygen and nitrogen are found in large quantities in the air around us.

b. They can be either liquids or gases. TRUE

Under certain temperatures any gas will transform into a liquid.

c.They turn from gas to liquid at the same temperature. FALSE

Oxygen it will pass into a liquid at -183 °C while nitrogen pass into a liquid at -195.8 °C.

d.They can be changed from gases to liquids by heating them. FALSE

The gases change to liquids by cooling them.

8 0

2 years ago