Propriedades da Água

10 Questions

Qual propriedade da água é responsável por permitir a formação de gelo que flutua na superfície dos corpos de água?

Densidade

Qual propriedade única da água é atribuída à formação de ligações de hidrogênio entre as moléculas?

Tensão superficial

Que propriedade da água permite que ela absorva e armazene uma grande quantidade de calor?

Capacidade térmica específica

Qual propriedade da água é fundamental para o ciclo da água, permitindo que ela se transforme em vapor na atmosfera?

Ponto de ebulição elevado

Quantas ligações de hidrogênio uma molécula de água pode formar com moléculas vizinhas?

Até quatro ligações

Qual é a propriedade da água que faz com que ela forme gotículas ou permaneça em forma esférica quando colocada em uma superfície sólida?

Tensão superficial

Qual é a capacidade térmica específica da água, representando a quantidade de calor necessária para elevar a temperatura de uma unidade de água em um grau Celsius?

4.18 kJ/kg°C

A que temperatura a água muda do estado líquido para o gasoso?

100°C

Qual das seguintes propriedades da água é responsável por sua capacidade de manter temperaturas consistentes em ambientes aquáticos?

Calor específico

Por que a água possui tensão superficial?

Devido às ligações de hidrogênio entre as moléculas de água

Study Notes

Water Properties

Water is an essential substance for life on Earth. It covers 71% of the Earth's surface, and its properties, such as surface tension, specific heat capacity, boiling point, density, and hydrogen bonding, play crucial roles in our daily lives and the functioning of the Earth's systems.

Surface Tension

Surface tension is the property that makes water form droplets or stay in a spherical shape when placed on a solid surface. It is a measure of the force required to increase the surface area of a liquid by creating a unit of new surface. The surface tension of water is about 72.8 dynes/cm at room temperature (20°C). This property is due to the cohesive force between water molecules, which are attracted to each other by hydrogen bonding.

Specific Heat Capacity

The specific heat capacity of water is the amount of heat required to raise the temperature of one unit of water by one degree Celsius. Water has a high specific heat capacity of 4.18 kJ/kg°C, which means it can store and release a large amount of heat energy. This property is significant for maintaining consistent temperatures in aquatic environments and for thermal energy storage.

Boiling Point

The boiling point of water is the temperature at which it transitions from a liquid to a gas. At standard atmospheric pressure (101.3 kPa), the boiling point of water is 100°C (212°F). This property is essential for the water cycle, as it is the temperature at which water evaporates into the atmosphere, becoming a part of the water vapor that forms clouds and returns to the Earth's surface as precipitation.

Density

The density of water is 1000 kg/m³, which is about 8.33 times denser than air. This property is related to the specific heat capacity, as water's high density allows it to absorb and store more heat energy. It also allows for the formation of ice, which is less dense than water, to float on the surface of water bodies.

Hydrogen Bonding

Hydrogen bonding is a type of intermolecular attraction that occurs between polar molecules, such as water. In water, hydrogen bonding is responsible for the unique properties of water, including its high surface tension, specific heat capacity, and boiling point. Each water molecule can form up to four hydrogen bonds with neighboring molecules, creating a complex network of attractions.

In conclusion, water's properties, including surface tension, specific heat capacity, boiling point, density, and hydrogen bonding, are crucial for its role in the Earth's systems and for life on Earth. These properties make water a versatile and essential substance for our planet.