Answer:
Pure substance B) Consists of a single element or type of compound.
Homogeneous A) Mixture that has its different components mixed evenly within the substance.
Heterogeneous D) Mixture that has its different components mixed unevenly within the substance.
Solution C) Liquid homogeneous mixture in which the solute is distributed evenly within the solvent.
Explanation:
Pure substances are a form of matter with definite constant composition and distinct properties. They consist of a single element or type of compound, as can be seen in its formula. Na, O₂, NaCl and H₂O are examples of pure substances.
When 2 or more pure substances are mixed together they form a mixture. If the mixture has its different components mixed <u>evenly</u> within the substance it is a homogeneous mixture. Whereas if the mixture has its different components mixed <u>unevenly</u> within the substance it is a heterogeneous mixture. The different parts observable in a heterogeneous mixture are known as phases.
In liquid homogeneous mixtures, we can recognize one or more substances that are in lower proportions (solutes) and one substance that is in greater proportion (solvent). This kind of mixture is known as a solution.
Answer:
Only gives spontaneous reaction.
Explanation:
A redox reaction will be spontaneous if standard reduction potential () of the reaction is positive. Because it leads to negative standard gibbs free energy change (), which is a thermodynamic condition for spontaneity of a reaction.
Where and represents standard reduction potential of reduction half cell and standard reduction potential of oxidation half cell.
(1) Oxidation: ;
Reduction: ;
So,
Hence this pair will give spontaneous reaction.
(2) Similarly as above,
Hence this pair will give non-spontaneous reaction.
(3) Similarly as above,
Hence this pair will give non-spontaneous reaction.
(4) Similarly as above,
Hence this pair will give non-spontaneous reaction.
Answer : The percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.
Explanation :
First we have to calculate the number of atoms in 5.5 wt% Pb and 94.5 wt% of Sn.
As, 207.2 g of lead contains atoms
So, 5.5 g of lead contains atoms
and,
As, 118.71 g of lead contains atoms
So, 94.5 g of lead contains atoms
Now we have to calculate the percent composition of Pb and Sn in atom.
and,
Thus, the percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.
Answer: With atomic number 20, calcium atoms have 20 positive protons, and the ion has only 18 electrons, which means the net charge is +2. Calcium ions are essential for muscle contractions, nerve impulses, and bone maintenance.
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