What are the uses of Evaporative Salts — Reading Comprehension

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"This NGSS-aligned middle school science passage explains the formation and diverse applications of evaporative salts, also known as evaporites. Students will learn how minerals like halite, gypsum, and potash precipitate from bodies of water as they evaporate in arid climates. The text details the sequential nature of this crystallization process and its significance for geological study. Key real-world connections are made, linking evaporites to everyday products such as table salt, road de-icers, drywall, and agricultural fertilizers. The passage uses clear, direct language and bolded vocabulary to make the complex topic accessible and engaging for students. It is designed to support the understanding of matter, chemical reactions, and Earth's systems, connecting to NGSS standards for physical and earth sciences."

CONTENT PREVIEW

Salt evaporation ponds are used to produce valuable evaporite minerals like halite and gypsum through the natural power of solar energy.

Evaporative salts, or evaporites, are a class of sedimentary minerals and rocks formed by the precipitation of salts from water. This process occurs when a body of water, such as a lake or a shallow sea, becomes concentrated with dissolved minerals as the water evaporates. In arid or semi-arid climates where the rate of evaporation is higher than the rate of water inflow, the remaining water becomes supersaturated with salts, which then crystallize and settle out. Common examples of evaporative salts include halite (table salt), gypsum, and potash. These minerals are crucial to both natural systems and human society.

The formation of these salts happens in a specific order. As a body of water evaporates, the minerals with the lowest solubility, like calcite and gypsum, precipitate first. Once the water becomes even more concentrated, the more soluble salts, such as halite, begin to crystallize. Finally, the most soluble salts, including potassium and magnesium chlorides, precipitate out. This sequential process results in layered deposits of different evaporite minerals, which geologists can study to learn about Earth's past climates.

Evaporative salts have a wide variety of uses that impact our daily lives. The most well-known evaporite is halite, which is used for food preservation and seasoning, de-icing roads in winter, and as a raw material in the chemical industry to produce substances like chlorine and sodium hydroxide. Gypsum is another vital evaporite, primarily used in construction to make drywall and plaster. Additionally, potash, a potassium-rich salt, is a key ingredient in agricultural fertilizers, helping to nourish crops and increase food production. These minerals are vital for everything from construction to food security.

Fun Fact: The Great Salt Lake in Utah is a modern example of an evaporite basin. Its high salinity, which is several times saltier than the ocean, allows for the commercial harvesting of salt and other minerals through natural solar evaporation.

What is the primary process by which evaporative salts are formed?

Volcanic activityPrecipitation from supersaturated waterErosion of rock layersPressure and heat deep underground

What are evaporites?

Rocks formed by volcanic eruptionsSedimentary minerals from evaporated waterIgneous rocks with a crystalline structureMinerals found only in deep ocean trenches

In the formation of evaporative salts, which type of minerals precipitates first?

Highly soluble salts like potashHaliteMinerals with the lowest solubilityAll minerals at the same time

According to the passage, what is a key use of gypsum?

Food preservationDe-icing roadsManufacturing fertilizersMaking drywall and plaster

The sequential precipitation of different salts from evaporating water can be used by geologists to understand what?

The age of the EarthThe composition of ancient oceansPast climate conditionsThe movement of tectonic plates

Which of the following is NOT listed as a use for halite in the passage?

Seasoning foodManufacturing fertilizersDe-icing roadsProducing chlorine

What is the main idea of the reading passage?

To explain the geological history of evaporites.To describe the chemical properties of different salts.To discuss the formation and diverse uses of evaporative salts.To highlight the economic importance of the Great Salt Lake.

If a company wants to produce a large amount of potash, they should look for a body of water that has undergone which process?

Volcanic activity to heat the waterComplete evaporation, leaving only the most soluble mineralsA constant, high inflow of fresh waterCrystallization of low-solubility salts, but not yet of halite