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Leya [2.2K]
3 years ago
12

Is this true or false ?

Chemistry
2 answers:
Natali5045456 [20]3 years ago
8 0

Answer:

False. Atom models have changed in the past centuries.

stiks02 [169]3 years ago
7 0

Answer:

false

Explanation:

The atom model has changed over time because of the discovery of subatomic particles

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Consider the reaction between hydrazine and hydrogen to produce ammonia, N2H4(g)+H2(g)→2NH3(g). Use enthalpies of formation and
sammy [17]

Answer:

The answer is explained below:

Explanation:

Given the chemical equation:

                   N2H4(g)+H2(g)→2NH3(g)

The standard enthalpy of formation is given by the following formula:

            ΔH^0 rxn = ∑ B reactants - ∑ product

       -187.78 kJ/mol = [( 1x B N-N) + (1 x B N-H ) + (1 x b H-H)] - [ 6 x B N-H]

       -187.78 kJ/mol = [( 1x B N-N)  +(4 x 391 kJ/mol) + (1 x 436  kJ/mol)] - [ 6x 391  kJ/mol ]

        -187.78 kJ/mol =  B N-N  + (1564 + 436 - 2346) kJ/mol

                                       B   = 158.22 kJ/mol

So, in this case the enthalpy of N-N bond is 158 kJ/mol

6 0
3 years ago
An isotope with a mass number of 193 has 116 neutrons. What is the atomic number of this
Zinaida [17]

Answer:

Atomic number of this  isotope = 77

Explanation:

Given that,

Mass number = 193

No of neutrons = 116

We need to find the atomic no of this isotope.

We know that,

Atomic mass = No of protons + No. of neutrons

Also, atomic no = no of protons

So,

Atomic mass = atomic no + No. of neutrons

⇒ Atomic no = Atomic mass - no of neutrons

Atomic no = 193 - 116

Atomic no = 77

Hence, 77 is the atomic no of the isotope.

6 0
3 years ago
How much energy does it take to melt 2 kg of ice? (Refer to table of<br> constants for water.)
ioda
It would be C

2 kg x 1000 g/kg x 1mol/18.02 x 6.03 kj/mol = 669kj


5 0
3 years ago
Read 2 more answers
Given the equation: 2H2 + O2 → 2H2O, how many moles of oxygen are needed to react with 13 moles of hydrogen
bulgar [2K]

Explanation:

2H2 + O2 = 2H2O

2mol. 1mol. 2mol

2mol reacts with 1mol

13mol reacts with x

x=<u>13mol</u><u> </u><u>×</u><u> </u><u>1mol</u>

<u> </u><u> </u><u> </u><u> </u><u> </u><u> </u><u> </u><u> </u><u> </u><u>2mol</u>

x= <u>13mol</u>

<u> </u><u> </u><u> </u><u> </u><u> </u><u> </u>2mol

x= 6.5mol of oxygen

6 0
2 years ago
Image included
Romashka [77]

Answer:1

Explanation:cause castle told me

4 0
2 years ago
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