I believe it is element As, for arsenic.
Answer:
By atomic number?
Explanation:
fingers crossed its right :/
Answer:
A. Has only one kind of atom
Explanation:
All forms of matter are composed of elements.
An element is a substance which cannot be broken down into simpler units or converted into other substances by ordinary chemical reactions. Each element is composed of only one kind of atoms which are unique to each element. There are three fundamental sub-particles present in atoms of elements; these are: protons, electrons and neutrons. An atom of an element differs from an atom of another element by its atomic number. The atomic number of an element is the number of protons present in the nucleus of the atom of that element. For example, hydrogen atoms has an atomic number of 1, while sodium atoms has an atomic umber of 11.
Atoms of the same element or different elements may combine together to form the molecules of a substance. For example, a molecule of hydrogen gas is made up of two atoms of hydrogen whereas a molecule of water is composed of two atoms of hydrogen and an atom of oxygen.
Elements can exist in any of the three physical states: solids, liquids or gases. For example, hydrogen exists as gas, mercury as a liquid, while gold exists as a solid.
Answer: Chemistry is the study of matter and the changes it undergoes.
An example of chemistry being used in the real world is how an ECG works. Chemistry is also sometimes considered the "central science". I hope this answer helped!! :)
In a 0.20 M solution, a weak acid is 3.0% dissociated, the value of
H₃O⁺ =9.19 × 10⁻² OH⁻ = 1.09 × 10⁻¹³, pH =1.04 , pOH = 12.96
<h3>What is pH?</h3>
The term pH, which originally stood for "potential of hydrogen" (or "power of hydrogen"), is used in chemistry to describe how acidic or basic an aqueous solution is. Lower pH values are summarized for acidic solutions (solutions with higher H+ ion concentrations) than for basic or alkaline solutions.
The pH scale is inversely indicates to the concentration of hydrogen ions in the solution and is logarithmic.
⇒pH = -log(
)
Acidic solutions are those with a pH below 7, and basic solutions are those with a pH above 7, at a temperature of 25 °C (77 °F). At this temperature, solutions with a pH of 7 are neutral (e.g. pure water). The pH neutrality relies on temperature, falling below 7 if the temperature rises above 25 °C.
Lets find [H₃O⁺]
Because 12.5% of the weak acid dissociated, 12.5% of the concentration of the weak acid also produced H3O.
H₃O = HA × 0.125
= 0.735 M × 0.125
= 9.19 × 10⁻²
Lets find [OH⁻]
Using the Kw = 1.0 × 10⁻¹⁴
Kw = [H₃O⁺][OH⁻]
[OH⁻] = Kw / [H₃O⁺]
= 1.0 × 10⁻¹⁴ / 9.19 × 10⁻²
= 1.09 × 10⁻¹³
Lets find pH
pH = -log[H₃O⁺]
= -log(9.19 × 10⁻²)
= 1.04
Lets find pOH
Using pH +pOH = 14
pH +pOH = 14
pOH = 14 - pH
= 14 - 1.04
= 12.96
Learn more about pH
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