Explanation:
Mike drives his car 60 km in 55minutes. What is its average speed in kilometers per hour ? A train travels 120 km in 2 hours and 30 .
Answer:
1,2 dichlorobenzene was used as the solvent for the diels alder reaction: <em>because the co elimination part of the reaction needs high temp and a high boiling point solvent such as 1,2 dichlorobenzene</em>
Explanation:
Diels-Alder Reaction is a useful synthetic tool to prepare cyclohexane rings. It is a process, which occurs in a single step that consists of a cyclic redistribution of its electrons. The two reagents are bond together through a cyclic transition state in which the two new C-C bonds are formed at the same time. For this to occur, most of the time, it is necessary a high temperature and high-pressure conditions. Since 1,2 dichlorobenzene has a boiling point of 180ºC is a good solvent for this type of reactions.
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
The maximum amount of hydrogen gas that can be prepared is if all the hydrogen from both compounds is released.
The hydrogen in 4.94 g of SrH2 is calculated from the mass ratios between Sr and H
1) H2 in SrH2
Sr atomic mass = 87.62 g/mol
H2 molar mass = 2.02 g/mol
Mass of 1 mol of SrH2 = 87.62 g / mol + 2.02 g/mol = 89.64 g/mol
Ratio of H2 to SrH2 = 2.02 g H2 / 89.64 g SrH2
Proportion: 2.02 g H2 / 89.64 gSrH2 = x / 4.93 g SrH2
=> x = 4.93 g SrH2 * 2.02 g H2 / 89.64 g SrH2 = 0.111 g H2
2) H2 in H2O
2.02 g H2 / 18.02 g H2O * 4.14 g H2O = 0.464 g H2
3) Total mass of hydrogen = 0.111 g + 0.464 g = 0.575 g
Answer: 0.575 g
Answer:
with the molecular formula C3H5(ONO2)3, has a high nitrogen content (18.5 percent) and contains sufficient oxygen atoms to oxidize the carbon and hydrogen atoms while nitrogen is being liberated, so that it is one of the most powerful explosives known.
Explanation:
NTG reduces preload via venous dilation, and achieves modest afterload reduction via arterial dilation. These effects result in decreased myocardial oxygen demand. In addition, NTG induces coronary vasodilation, thereby increasing oxygen delivery.
