C) They each form similar compounds when combined with oxygen.
Explanation:
The given elements have a common characteristics as they each form similar compounds when combined with oxygen.
Beryllium, magnesium and calcium all are located in the alkaline earth group.
Elements in the same group have the same chemical properties.
- Density and melting point are physical properties of matter which varies down a group on the periodic table.
- Their reaction with oxygen denotes a statement of their chemical properties.
- Chemical properties of matter is a function of their valency.
- Group two elements have a valency of two. They have two electrons in their outermost shell.
- Therefore, they all form ionic bonds when they react with oxygen.
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The most common method astronomers use to determine the composition of stars, planets, and other objects is spectroscopy. This process utilizes instruments with a grating that spreads out the light from an object by wavelength. This spread-out light is called a spectrum. Every element has a unique fingerprint that allows researchers to determine what it is made of.
The fingerprint often appears as the absorption of light. Every atom has electrons, and these electrons like to stay in their lowest-energy levels. But when photons carrying energy hit an electron, they can push it to higher energy levels. This is absorption, and each element’s electrons absorb light at specific wavelengths related to the difference between energy levels in that atom. But the electrons want to return to their original levels, so they don’t hold onto the energy for long. When they emit the energy, they release photons with exactly the same wavelengths of light that were absorbed in the first place. An electron can release this light in any direction, so most of the light is emitted in directions away from our line of sight. Therefore, a dark line appears in the spectrum at that particular wavelength.
Because the wavelengths at which absorption lines occur are unique for each element, astronomers can measure the position of the lines to determine which elements are present in a target. The amount of light that is absorbed can also provide information about how much of each element is present.
<span>This would be the activation energy. This is usually in the form of heat, which allows the reaction to undergo some sort of transition. Many times, enzymes can be used as catalysts to lower the activation energy required for the reaction to take place.</span>
Answer:
The pressure is 5.62 atm.
Explanation:
An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:
P * V = n * R * T
In this case:
- P= ?
- V= 5.005 L
- n= 1.255 mol
- R= 0.082
- T= 273.5 K
Replacing:
P* 5.005 L= 1.255 mol* 0.082 *273.5 K
Solving:
P= 5.62 atm
<u><em>The pressure is 5.62 atm.</em></u>
