Ques:Q: Which type of substance is considered a proton donor in a reaction? Read this paragraph and choose the correct option from the provided answers: The Arrhenius definition of acids and bases is somewhat limited. There are some compounds whose properties suggest that they are either acidic or basic, but which do not qualify according to the Arrhenius definition. An example is ammonia (NH 3 ). Its aqueous solution turns litmus blue, it reacts with acids, and displays all the other properties of a base. However, it does not contain the hydroxide ion. In 1923, a broader definition of acids and bases was independently proposed by Danish chemist Johannes Brnsted (1879-1947) and English chemist Thomas Lowry (1874-1936). A Brnsted-Lowry acid is a molecule or ion that donates a hydrogen ion in a reaction. A Brnsted-Lowry base is a molecule or ion that accepts a hydrogen ion in a reaction. A hydrogen ion is commonly referred to as a proton, and so acids and bases are proton donors and proton acceptors respectively according to the Brnsted-Lowry definition. All substances that are categorized as acids and bases under the Arrhenius definition are also defined as such under the Brnsted-Lowry definition. The new definition, however, includes some substances that are left out according to the Arrhenius definition. Choices: - base - carbon - oxygen - acid A:

Ans:acid
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Ques:Q: What are the two hormones primarily responsible for maintaining homeostasis of blood glucose levels? Read this paragraph and choose the correct option from the provided answers: Hormonal Regulation of Metabolism Blood glucose levels vary widely over the course of a day as periods of food consumption alternate with periods of fasting. Insulin and glucagon are the two hormones primarily responsible for maintaining homeostasis of blood glucose levels. Additional regulation is mediated by the thyroid hormones. Choices: - dopamine and melanin - anabolic and metabolic - insulin and estrogen - insulin and glucagon A:

Ans:insulin and glucagon
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Ques:Q: What is the name of the magnetic material found in lava? Read this paragraph and choose the correct option from the provided answers: Magnetite is a magnetic mineral found in lava. The magnetite points to the magnetic north pole when it cools. Choices: - meteorite - hemoglobin - magnemite - magnetite A:

Ans:magnetite
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Ques:Q: What makes a complete orbit around the earth once every 29 1/2 days? Read this paragraph and choose the correct option from the provided answers: Choices: - Mars - the Sun - Gemini - the moon A:

Ans:
the moon
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