Chemistry Context - Grade 7

<p>100°C (C)</p> Signup and view all the answers

<p>Evaporation occurs only at the surface of the liquid. (A)</p> Signup and view all the answers

<p>The temperature where a solid turns into a liquid. (D)</p> Signup and view all the answers

<p>Fixed volume (C)</p> Signup and view all the answers

<p>Color (C)</p> Signup and view all the answers

<p>2 atoms of hydrogen and 1 atom of oxygen (B)</p> Signup and view all the answers

<p>Saltwater (C)</p> Signup and view all the answers

<p>It can dissolve a wide range of substances. (A)</p> Signup and view all the answers

<p>Evaporation, condensation, and sublimation (A)</p> Signup and view all the answers

<p>It provides energy for evaporation. (D)</p> Signup and view all the answers

<p>80% (B)</p> Signup and view all the answers

<p>Pure substances and mixtures (C)</p> Signup and view all the answers

<p>Urban and industrial needs (D)</p> Signup and view all the answers

The study of the properties, composition, structure, and transformations of substances (elements and compounds), along with the energy changes involved.

These are characteristics that can be observed or measured without changing the substance's chemical composition.

These describe how a substance reacts with other substances or changes its chemical composition.

Solid, liquid, gas, and plasma are the four states of matter, each with unique properties.

The temperature at which a substance transitions from solid to liquid.

The temperature at which a substance transitions from liquid to solid.

The temperature at which a liquid changes into a vapor.

Evaporation occurs only on the surface of a liquid at any temperature, while boiling happens throughout the entire liquid at a specific temperature.

The continuous movement of water between Earth's surface and the atmosphere, driven by solar energy. Involves evaporation, condensation, precipitation, runoff, infiltration, and transpiration.

Water is known as the 'universal solvent' because it has the ability to dissolve a wide range of substances, making it essential for many chemical reactions and processes in nature and living organisms.

Water is the main component of all living organisms, making up a significant percentage of their body weight. This is crucial for maintaining various life functions like cell structure, nutrient transport, and temperature regulation.

The molecule of water consists of two atoms of hydrogen (H) and one atom of oxygen (O), represented by the chemical formula H2O. This simple structure gives water its unique properties.

The most abundant kind of water on Earth is saltwater, found in oceans and seas. It comprises the majority of the planet's water and plays a significant role in Earth's climate and ecosystems.

The energy from the sun drives the water cycle. It heats the surface of the Earth, causing evaporation of water. This evaporated water then condenses into clouds, eventually leading to precipitation.

Matter can be categorized into pure substances and mixtures. Pure substances are further classified into elements and compounds. Mixtures, on the other hand, are categorized into homogeneous and heterogeneous mixtures.

Water vapor is the gaseous form of water, formed when liquid water evaporates. It is an important component of the atmosphere and contributes to cloud formation and precipitation.