Ответы
a) Heat applied to an egg also causes the water within the egg to evaporate. Water molecules gain energy from the heat, enabling them to break free from the liquid state and transform into gas. The evaporation of water leads to the concentration of proteins and other solutes in the egg, contributing to the overall solidification and cooking process.
b) Jelly typically contains gelatin. When gelatin is mixed with water, its molecules disperse and form a loose, tangled network throughout the liquid. When jelly is dissolved in a smaller amount of water, there is a higher concentration of gelatin molecules in the mixture. This higher concentration promotes more frequent interactions between the gelatin molecules, allowing them to come into closer proximity to each other.
c) When a candle burns, it undergoes a combustion process that requires three essential components: fuel (wax), oxygen, and heat. The heat melts the wax, which is then drawn up the wick, vaporized, and reacts with oxygen to sustain the flame. In still air, the combustion process relies on the natural convection currents to bring fresh oxygen to the flame. However, in a slight draught, the movement of air helps in two ways. Firstly, it brings in a continuous supply of fresh oxygen to the flame, ensuring efficient combustion. The enhanced oxygen supply increases the rate at which the fuel (wax) is consumed.
d) Powdered chalk has a significantly larger surface area compared to a lump of chalk. When chalk is powdered, it is broken down into smaller particles, increasing the overall exposed surface area available for interaction with the vinegar. This increased surface area provides more sites for the vinegar molecules to come into contact with the chalk particles.
e) The increased temperature of the solution or acid affects the reactivity of the system. In the case of magnesium, higher temperatures promote more vigorous reactions. When the magnesium ribbon comes into contact with the warmed solution or acid, the thermal energy facilitates the breaking of bonds between the magnesium atoms, allowing them to react with the surrounding molecules of the solution or acid more readily. This increased reactivity accelerates the dissolution process.
f) Rennin plays a key role in the coagulation process. The loss of inhibition allows the rennine micelles to aggregate and bind together more tightly, forming a cohesive curd. Also, rennin's action is further aided by the presence of calcium ions in milk. Calcium ions help stabilize the newly formed curd by binding to the negatively charged regions on the casein proteins. This binding reinforces the structure of the curd and promotes the formation of a cohesive mass.