Pure metals possess few important physical and metallic properties, such as melting point, boiling point, density, specific gravity, high malleability, ductility, and heat and electrical conductivity. These properties can be modified and enhanced by alloying it with some other metal or nonmetal, according to the need.
Alloys are made to:
Enhance the hardness of a metal: An alloy is harder than its components. Pure metals are generally soft. The hardness of a metal can be enhanced by alloying it with another metal or nonmetal.
Lower the melting point: Pure metals have a high melting point. The melting point lowers when pure metals are alloyed with other metals or nonmetals. This makes the metals easily fusible. This property is utilized to make useful alloys called solders.
Enhance tensile strength: Alloy formation increases the tensile strength of the parent metal.
Enhance corrosion resistance: Alloys are more resistant to corrosion than pure metals. Metals in pure form are chemically reactive and can be easily corroded by the surrounding atmospheric gases and moisture. Alloying a metal increases the inertness of the metal, which, in turn, increases corrosion resistance.
Modify color: The color of pure metal can be modified by alloying it with other metals or nonmetals containing suitable color pigments.
Provide better castability: One of the most essential requirements of getting good castings is the expansion of the metal on solidification. Pure molten metals undergo contraction on solidification. Metals need to be alloyed to obtain good castings because alloys
Moving from Ethanol through Propanol to Butanol the physical properties like boiling points, surface tension and viscosity increases because of the increases in intermolecular interactions between the molecules of given compounds.
Explanation:
Ethanol, propanol and butanol all have hydroxyl groups in common, means all have hydrogen bond intractions between their molecules. So, taking the hydrogen bonding interaction constant we are left with only the difference in the number of carbon atoms.
Butanol has the greatest physical properties than other two because it has four carbon atom chain. So, as we know the London Dispersion forces or Van der Waal forces increases with increase in molecular size and chain length of hydrocarbon.
Therefore, the strength of London forces is greater in butanol than other two while ethanol has the smallest chain comparatively hence, lowest physical properties.
Answer:
D, E and F
Explanation:
About tetrachloro cobalt complexes, the following facts have been observed
- Color of the tetrachloro cobalt complexes is blue.
- They do not decompose on heating that means synthesis of tetra chloro is endothermic.
About hexa aqua cobalt complexes, the following facts have been observed
- Color of the hexa aqua cobalt complexes is pink color.
- They decompose on heating and remain stable on cooling that means process of synthesis of hexa aqua cobalt complexes is exothermic.
Based on above, the correct statements are:
The correct is chloro cobalt complex is blue and aqua cobalt
complex is pink.
The chloro complex is favored by heating.
If the chloro complex is a product, then the reaction must be endothermic.
The correct options are D, E and F.
Answer:
In each Amplify Science unit, students figure out
a phenomenon by asking questions, gathering
evidence, and coming up with an explanation of how
the phenomenon works. The Coherence Flowchart
visually represents the storyline of the unit, showing
the coherent flow of questions, evidence, and ideas that
support students as they build complex explanations
of the unit’s anchor phenomenon. The Coherence
Flowchart on the following pages (one chapter per
page) can be used to see the connections between
the questions that drive students’ experiences, the
evidence they gather, the ideas they figure out, and the
new questions that those ideas generate. The diagram
to the right explains the structure of a chapter in the
Explanation:
