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olganol [36]
2 years ago
10

Why did we change our understanding of where life comes from?

Chemistry
1 answer:
Andru [333]2 years ago
8 0

Answer:

whathappensinthisstory

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We can change a gas to liquid by_________ the temperature and_________
Tpy6a [65]
Decreasing, Removing
6 0
3 years ago
Ergosterol, a precursor of vitamin D, has δmax = 282 nm and molar absorptivity ε = 11,900 M-1cm-1. What is the concentration of
meriva

Answer:

3.6 × 10⁻⁵ M

Explanation:

Ergosterol has a maximum absorbance at λ = 282 nm. The absorbance of an analyte is related to its concentration through the Beer-Lambert's law.

A = ε × <em>l</em> × c

where,

A: absorbance

ε: molar absorptivity

<em>l</em>: optical path length

c; molar concentration

c = A / ε × <em>l </em>= 0.43 / (11,900 M⁻¹cm⁻¹) × 1.00 cm = 3.6 × 10⁻⁵ M

3 0
3 years ago
Which pure substance is made of only one kind of atom?
aleksley [76]

Answer:

the answer is D i believe. i am not shure but im like 70% sure

7 0
3 years ago
Helpppppppppppppp please
Mama L [17]
1)
-Lithium: Lithium got 3 protons, so it atomic number is 3. It is located on the first column of the periodic table, and belonging to the alkali metal. So lithium is a metal. Lithium is highly reactive.
-Neon: It is located on the 18th column of the periodic table, and belong to the noble gases. So Neon is a nonmetal. Neon's reactivity is very low.
-Fluorine: Located on the 17th column of the periodic metal, fluorine is a nonmetal, and belong to the halogen family. Fluorine's reactivity is high.

2)
-Vertical columns of the periodic table are called columns. There is 18 column in the periodic table, and each one represent a chemical family.
-Horizontal rows of the periodic table care called periods. There is 7 periods in the periodic table.
-The number of protons in an atom is that element's atomic number. And since the atom is electrically neutral, the number of protons is equal to the number of electrons. So if you have the number of electrons, you can still find the atomic number.
-The total of protons and neutrons in an atom is that element's atomic mass. Based on the formula A = Z + N, where A represents the atomic mass, Z the atomic number (number of protons) and N the number of neutrons.
-The elements in group 1 are the most reactive metals. This group is called the Alkali metals. They only have 1 electron in their outer shell which makes them always ready to lose an electron in an ionic bonding.
-The elements in group 17 are the most reactive nonmetals. This group is called the Halogens, with 7 electrons in their outer shell which makes them always ready to win an electron in an ionic bonding.
-The elements in group 18 are the most unreactive elements. This group is called the Noble gases. Their outer shell is always full, so it can't do reactions.

Hope this Helps! :)

4 0
3 years ago
1. Which of the following is a correctly written thermochemical equation?
WITCHER [35]

Explanation:

1. Thermochemical equation is balance stoichiometric chemical equation written with the phases of the reactants and products in the brackets along with the enthalpy change of the reaction.

The given correct thermochemical reactions are:

Fe(s)+O_2(g)\rightarrow Fe_2O_3(s),\Delta H = 3,926 kJ&#10;

C_3H_8(g)+5O_2 (g)\rightarrow 3CO_2 (g)+4H_2O(l),\Delta H= 2,220 kJ/mol

2. Phase change affect the value of the enthalpy change of the thermochemical equation. This is because change in phase is accompanied by change in energy. For example:

H_2O(s)\rightarrow H_2O(g),\Delta H_{s}=51.1 kJ/mol

H_2O(l)\rightarrow H_2O(g),\Delta H_{v}=40.65 kJ/mol

In both reaction phase of water is changing with change in energy of enthalpy of reaction.

7 0
3 years ago
Read 2 more answers
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