Answer:
Explanation:
The theory or working principle of Atomic Emission Spectroscopy involves the examination of the wavelengths of photons discharged by atoms and molecules as they transit from a high energy state to a low energy state. A characteristic set of wavelengths is emitted by each element or substance which depends on its electronic structure.
The correct answer is D. In a police interrogation room, questioning the suspect.
Explanation:
Forensic scientists are experts who use science as part of criminal investigations. Indeed, the main role of these experts is to deal with the evidence related to the crime to help authorities understand how the crime occurred and who was involved in this.
Because of this, the forensic scientist's role includes collecting evidence, analyzing samples, participating as witnesses in trials, and in some cases teach other experts about techniques. However, forensic scientists cannot interrogate suspects as they only deal with evidence and this process is in charge of the police.
1. Elements are composed of atoms that are indestructible
2. All atoms of a given element are identical; same size/mass/chemical properties
3. Atoms of 1 element are different from the atoms of other elements
4. Compounds are composed of atoms with more than 1 element. The relative number of atoms for each element are of a given compound are always going to be the same.
(Extra one) 5. Chemical reactions are only ever going involve the rearrangement of the atoms. Atoms are not created/destroyed during the chemical reactions. (Law of Conservation of Mass: nothing can ever be created or destroyed.)
Answer:Explanation:Protons and other subatomic particles will be discussed a little later. The atoms of different elements are different from each other because they have different numbers of protons. The graphic below illustrates this point by showing the atoms of two elements in the containers of oxygen and hydrogen.
Answer:
The change in enthalpy in the combustion of 3 moles of methane = -2406 kJ
Explanation:
<u>Step 1: </u>The balanced equation
CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) ΔH = -802 kJ
<u>Step 2:</u> Given data
We notice that for 1 mole of methane (CH4), we need 2 moles of O2 to produce : 1 mole of CO2 and 2 moles of H20.
The enthalpy change of combustion, given here as Δ
H
, tells us how much heat is either absorbed or released by the combustion of <u>one mole</u> of a substance.
In this case: we notice that the combustion of 1 mole of methane gives off (because of the negative number), 802.3 kJ of heat.
<u>Step 3: </u>calculate the enthalpy change for 3 moles
The -802 kj is the enthalpy change for 1 mole
The change in enthalpy for 3 moles = 3* -802 kJ = -2406 kJ
The change in enthalpy in the combustion of 3 moles of methane = -2406 kJ
