ANSWER- B
Atomic emission spectra are produced when excited electrons return to the ground state. The emitted light corresponds to energies of the specific electrons.
<span>Answer: a mixture.
</span><span>Justification:</span>
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</span><span>1) Pure substances have a definite chemical formula: the same kind of atoms with the same fixed ratios and chemical bonds. Therefore, the percents of each element do not varye.
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2) Elements and compounds are pure substaces. For example, Fe, Mg, Ti, are elements, and CO₂, CO, H₂CO₃ are compounds. Each of them will have always the same kind of atoms, in the same ratio and with the same chemcial bonds. Therefore the percents of the elements do not varye.
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<span>3) Mixtures are formed by the physical combination (not chemical bonds) of different elements or compounds in variable proportions. As indicated, this describes the material bronze, in virtue of the variation of its composition. Other examples of mixtures are solutions (like brines), air, ocean water, and milk: different brines, different oceans and different milk have different contents of elements or compounds.
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Answer:
A. China And Japan.
Explanation:
The species is native to China/Japan and was introduced into the United States in the mid-1990s, possibly stowing away in a shipping container. The presence of this stink bug is concerning for farmers because it feeds on a large number of high-value crops and ornamental plants in its immature and adult life stages.
Answer:
A. The human body can break down complex carbohydrates into sugar molecules that provide energy.
Explanation:
Strings of glucose, form complex carbohydrates such as starch and glycogen. Glycogen which is a stored form of glucose in humans is a source of long-term energy, and a complex carbohydrate because glycogen can be converted to glucose-1-phosphate which can enter the glycolytic cycle to generate Adenosine triphosphate which is a unit of energy.
This stored form of energy can be slowly broken down to release energy when needed by the body. During exercise, for instance, glycogen can slowly release ATP needed for energy.
Hey there!
Density = 2.75 g/cm³
Volume = 8 cm³
Mass = ?
Therefore:
Mass = Density * volume
Mass = 2.75 * 8
Mass = 22 g
