Answer:
3) Each sample has the same number of molecules
Explanation:
1 mol are 6,022x10²³ particles. Moles of a chemical substance represent the number of molecules that this chemical has.
Thus, one mol of oxygen are 6,022x10²³ molecules of oxygen and one mol of nitrogen are 6,022x10²³ molecules of nitrogen.
Right answer is:
3) Each sample has the same number of molecules.
I hope it helps!
N,Br
a. CH4 and C2H4
b. PbCl2 and PbCl4
c. N2O5 and NO2
d. C2H6 and C4H12
Answer: The correct option is d.
Explanation: Empirical formula is a chemical formula which has the simplest ratio of elements present in a chemical compound.
From the given following pairs, the pair which shares the same empirical formula is
Empirical formula of is (by dividing the coefficients of by 3)
Empirical formula of is (by dividing the coefficients of by 3)
Both the chemical formulas have same empirical formula. Hence, the correct option is d.
b. reaction
c. dynamic
d. elementary
Magnetizing steel is a physical change, not a chemical change because it does not change the chemical composition of the steel.
A chemical change is a change in which new substances are formed. This is because the atoms in the original substances are rearranged to form new atoms or molecules. There is no chemical change when magnetizing steel. For example, when iron rusts, it reacts with oxygen to form a new substance called iron oxide.
A physical change is a change in which the form of a substance is changed, but the substanceitself is not changed. For example, when you melt ice, you are changing the form of water from a solid to a liquid, but the water itself is not changed.
When you magnetize steel, you are simply aligning the magnetic domains in the steel. Magnetic domains are regions of a material that have a net magnetic field. When the magnetic domains are aligned, the steel becomes magnetized.
Magnetizing steel does not change the chemical composition of the steel. The steel is still made up of the same atoms, and the atoms are still arranged in the same way. The only difference is that the magnetic domains are aligned, which gives the steel its magnetic properties.
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Democritus, an ancient Greek philosopher who lived around 460-370 BCE, made significant contributions to the early development of the atomic theory.
His ideas laid the foundation for the later development of modern atomic theory. Here's how Democritus contributed to the atomic theory and the structure of the atom:
Concept of Indivisible Atoms: Democritus proposed that everything in the physical world was made up of tiny, indivisible particles called "atoms." The word "atom" itself is derived from the Greek word "atomos," which means "indivisible" or "uncuttable." Democritus believed that atoms were the fundamental building blocks of matter and that they could not be divided into smaller parts.
Various Shapes and Sizes: Democritus suggested that atoms could vary in shape and size. He proposed that different substances were composed of atoms with different shapes, which explained the diversity of matter in the universe.
Empty Space: Democritus also introduced the idea of "void" or empty space between atoms. He believed that atoms were in constant motion and that the void allowed for this motion.
Lack of Experimental Evidence: It's important to note that while Democritus made these philosophical speculations about atoms, he did not provide any experimental evidence to support his ideas. His atomic theory was largely based on reasoning and thought experiments rather than empirical data.
Democritus' atomic ideas were influential, but they were largely overshadowed by the more prominent theories of his contemporary, Aristotle, which emphasized the existence of four fundamental elements (earth, water, air, and fire). It wasn't until much later, in the 19th century, that John Dalton and others developed the modern atomic theory, which incorporated experimental evidence and refined our understanding of atoms as the smallest units of matter that retain the properties of chemical elements.
Democritus contributed to the atomic theory by proposing the concept of indivisible atoms as the fundamental building blocks of matter, but his ideas lacked experimental support and were not widely accepted in his time.