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3 years ago

I need help writing a LAB REPORT about NATURAL SELECTION

Chemistry

1 answer:

LekaFEV [45]3 years ago

5 0

Answer:

Translate from Ukrainian.

У цей приклад я візьму селекції пшениці. Коли ми будемо говорити про селекцію цього злака, то ми можемо отримати меньшу собівартість, та вартість вирощування. Збільшена урожайність, та менша потреба в гербіцидах, пестицидах, та інсектицидах це теж наслідок. Тому селекція це майбутнє!

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The following thermochemical equation is for the reaction of nitrogen(g) with oxygen(g) to form nitrogen dioxide(g). N2(g) + 2O2

Rzqust [24]

<u>Answer:</u> The mass of nitrogen gas reacted to produce given amount of energy is 5.99 grams.

<u>Explanation:</u>

The given chemical reaction follows:

$N_2(g)+2O_2(g)\rightarrow 2NO_2(g);\Delta H=66.4kJ$

We know that:

Molar mass of nitrogen gas = 28 g/mol

We are given:

Enthalpy change of the reaction = 14.2 kJ

To calculate the mass of nitrogen gas reacted, we use unitary method:

When enthalpy change of the reaction is 66.4 kJ, the mass of nitrogen gas reacted is 28 grams.

So, when enthalpy change of the reaction is 14.2 kJ, the mass of nitrogen gas reacted will be = $\frac{28}{66.4}\times 14.2=5.99g$

Hence, the mass of nitrogen gas reacted to produce given amount of energy is 5.99 grams.

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3 years ago

The molecules of a substance must have what characteristics in order to be flexible

Goryan [66]

Answer:
<span>The molecules of a substance which must have the <u>a</u></span><u>bility to move past one another</u> are said to be flexible.

Explanation:
Those substances are said to be flexible which can be bent without breaking. There are many substances which are hard in nature but still can be bent. The hardness of such materials is due to strong interactions between the molecules and the flexibility comes due to their amorphous backbone. Therefore, greater the crystalline level of macromolecules lesser is the flexibility and greater the amorphous character greater is the flexibility and vice versa. Also, the flexibility of polymers is increased by adding plastisizers in it. Plastisizers make the hard polymers flexible by breaking the crosslinkers and enabling the macromolecules to move past one another.

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2 years ago

What is the maximum number of covalent bonds that can be formed by one carbon atom? 1 2 3 4

Rainbow [258]

The maximum number of covalent bonds formed by a single carbon atom is 4

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3 years ago

2. How much heat must be absorbed by a sample of 1337 grams (g) of ice at -10°C in order to turn it into water vapor at 120°C?

olya-2409 [2.1K]

Answer:

Explanation:

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2 years ago

antimony has two naturally occuring isotopes, sb121sb121 and sb123sb123 . sb121sb121 has an atomic mass of 120.9038 u120.9038 u

Luda [366]

Considering the definition of atomic mass, isotopes and atomic mass of an element, sb121 has a percent natural abundance of 0.5726 or 57.26% and sb123 has a percent natural abundance of 0.4284 or 42.84%.

<h3>Definition of atomic mass</h3>

The atomic mass is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.

<h3>Definition of isotope</h3>

Isotopes are the chemical elements in which atomic numbers are the same, but the number of neutrons is different.

<h3>Definition of atomic mass</h3>

The atomic mass of an element is the weighted average mass of its natural isotopes.

This is, the atomic masses of elements are usually calculated as the weighted average of the masses of the different isotopes of each element, considering the relative abundance of each of them.

<h3>Percent natural abundance of each isotope</h3>

In this case, antimony has two naturally occuring isotopes, sb121 and sb123. You know:

sb121 has an atomic mass of 120.9038 u.
sb121 has a percent natural abundance of x.
sb123 has an atomic mass of 122.9042 u.
sb123 has a percent natural abundance of 1 -x (or, what is the same, the abundance is 100% - x%, since both isotopes form 100% of the element.)
Antimony has an average atomic mass of 121.7601 u