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4 years ago

Please help! Best answer will receive brainliest. 15 points.

Chemistry

1 answer:

9966 [12]4 years ago

3 0

Answer:

Melting of ice is a physical change and during this change latent heat of fusion, that is, heat required to convert 1 g of a solid substance into liquid state will keep the temperature constant unless and until all the solid changes into liquid. On the other hand, a change in which a new product is formed due to change in chemical composition of the reacting species is known as a chemical change. During a chemical change, there will occur change in temperature. So, when a substance is set on fire then there will occur change in temperature of the substance. Hence, it means it is a chemical change.

Explanation:

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The elements least likely to form bonds are found in which group?

taurus [48]

Answer:

Noble gases are a unique set of elements in the periodic table because they don't naturally bond with other elements.

Explanation:

HAVE A GOOD DAY!

4 0

3 years ago

Given that the initial rate constant is 0.0110s−1 at an initial temperature of 21 ∘C , what would the rate constant be at a temp

gulaghasi [49]

The rate constant is mathematically given as

K2=2.67sec^{-1}

<h3>What is the Arrhenius equation?</h3>

The rate constant for a particular reaction may be calculated with the use of the Arrhenius equation. This constant can be stated in terms of two distinct temperatures, T1 and T2, as follows:

$ln(\frac{K2}{K1})= (\frac{Ea}{R})*(\frac{1}{T1}-\frac{1}{T2})$

Therefore

KT1= 0.0110^{-1}

T1= 21+273.15

T1= 294.15K

T2= 200

T2=200+273.15

T2= 473.15K

Ea= 35.5 Kj/Mol

Hence, in j/mol R Ea is

Ea=35.5*1000 j/mol R

$ln(\frac{K2}{0.0110})= (\frac{35.5*1000}{8.314})*(\frac{1}{294.15}-\frac{1}{473.15}\\\\ln(\frac{K2}{0.0110})=5.492$

K2/0.0110 =e^(5.492)

K2/0.0110 =242.74

K2= 242.74*0.0110

K2=2.67sec^{-1}

In conclusion, rate constant

K2=2.67sec^{-1}

Read more about rate constant

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5 0

2 years ago

#1: How are the elements arranged in the modern periodic table?

Alekssandra [29.7K]

1- The correct answer is C :

the elements arranged in the modern periodic table by increasing atomic number.

The explanation:

-The elements in the periodic table are arranged to increase the atomic number. All of these elements display several other trends and we can use the periodic law and table formation to predict their chemical, physical, and atomic properties.

2- The correct answer is C:

strontium, magnesium, calcium, beryllium are the elements which have similar properties.

The explanation:

-strontium, magnesium, calcium, beryllium, these belong to the alkaline earth metal group.

Because the outer electron structure in all of these elements is similar, they all have somewhat similar chemical and physical properties .

3- The correct answer is A :

Potassium

The explanation:

-The elements potassium and sodium have similar chemical properties because they have the same number of valence electrons and form +1 ions.

4- The correct answer is D

The explanation:

Mendeleev didn't include helium, neon, and argon in his periodic table because these elements had not yet been discovered.

5- The correct answer is B:

The periodic law describes trends seen across periods within the periodic table.

The explanation:

When the chemical elements are arranged, there is a pattern called the “periodic law” in their properties, in which elements in the same column (group) have similar properties

4 0

3 years ago

Read 2 more answers

A sample of octane undergoes combustion according to the equation 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O ΔH°rxn = -11018 kJ. What mas

Anna71 [15]

Answer:

$\large \boxed{\text{528.7 g} }$

Explanation:

It often helps to write the heat as if it were a reactant or a product in the thermochemical equation.

Then you can consider it to be 11018 "moles" of "kJ"

We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.

M_r: 32.00

2C₈H₁₈ + 25O₂ ⟶ 16CO₂ + 8H₂O + 11 018 kJ

n/mol: 7280

1. Moles of O₂

The molar ratio is 25 mol O₂:11 018 kJ

$\text{Moles of O}_{2} = \text{7280 kJ} \times \dfrac{\text{25 mol O}_{2}}{\text{11 018 kJ}} = \text{16.52 mol O}_{2}$

2. Mass of O₂

$\text{Mass of C$_{8}$H}_{18} = \text{16.52 mol O}_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \textbf{528.6 g O}_{2}\\\text{The reaction requires $\large \boxed{\textbf{528.67 g O}_{2}}$}$

3 0

3 years ago

Oxidation and reduction reactions (redox) involve the loss and gain of electrons. Half-reactions are a way for us to keep track

jok3333 [9.3K]

Answer:

Electrons are lost during oxidation (LEO)

4 0

3 years ago