Answer:
<em>From a balanced chemical equation the relationships </em><u>of the amount of reactants and products, either as number of units (moles) or as mass (grams), </u><em>can be determined. </em>
Explanation:
Since reactants combine in a fixed ratio to form a fixed amount of products, the law of mass conservation permits to state cuantitative relationships between the amounts of rectants and products, and this is represented through a balanced chemical equation.
The balanced chemical equation represents the reactants and products using the chemical composition of each substance (consisting of chemical symbols and subscritps) and shows the relations in which they react or are produced using numbers as coefficients.
For example:
- <em>Balanced chemical equation:</em> 1CH₄(g+ 2O₂(g) → 1CO₂(g) + 2H₂O(g)
1 molecule CH₄ : 2 molecules O₂ : 1 molecule CO₂ : 2 molecules H₂O
1 mole CH₄ : 2 moles O₂ : 1 mole CO₂ : 2 moles H₂O
16.04 g CH₄ : 64.00 g O₂ : 44.01 g CO₂ : 36.03 g H₂O
(80.04 g reactants = 80.04 g products)
Answer:
Substances can change phase—often because of a temperature change. At low temperatures, most substances are solid; as the temperature increases, they become liquid; at higher temperatures still, they become gaseous.
The process of a solid becoming a liquid is called melting. (an older term that you may see sometimes is fusion). The opposite process, a liquid becoming a solid, is called solidification. For any pure substance, the temperature at which melting occurs—known as the melting point—is a characteristic of that substance. It requires energy for a solid to melt into a liquid. Every pure substance has a certain amount of energy it needs to change from a solid to a liquid. This amount is called the enthalpy of fusion (or heat of fusion) of the substance, represented as ΔHfus. Some ΔHfus values are listed in Table 10.2 “Enthalpies of Fusion for Various Substances”; it is assumed that these values are for the melting point of the substance. Note that the unit of ΔHfus is kilojoules per mole, so we need to know the quantity of material to know how much energy is involved. The ΔHfus is always tabulated as a positive number. However, it can be used for both the melting and the solidification processes as long as you keep in mind that melting is always endothermic (so ΔH will be positive), while solidification is always exothermic (so ΔH will be negative).
Table 10.2 Enthalpies of Fusion for Various Substances
Explanation:
To determine the volume of the gas mixture, we first need to determine the total pressure of the mixture. To do this, we use the definition of the partial pressure of a component in the gas mixture. The partial pressure is the pressure of a component as if it were alone in the container. It is equal to the mole fraction of the component times the total pressure of the system. From this, we determine total pressure.
Pneon = xneonP
P = Pneon / xneon
P = 8.87 kPa / (225 / (225 + 320 + 175))
P = 8.87 kPa / 0.3125 = 28.384 kPa
Assuming ideal gas, we use PV=nRT to calculate for the volume,
PV = nRT
V = nRT / P
n = 225 mg ( 1 mmol / 20.18 mg) + 320 mg ( 1 mmol / 16.05 mg ) + 175 mg ( 1 mmol / 39.95 mg ) = 35.47 mg = 35467.0 g
V = 35467.0 (8.314) (300) / (28384) = 3116.68 m^3
<h2>5060 have three significant figures : Explanation given below </h2>
Explanation:
Significant figures
The significant figures (also known as the significant digits and decimal places) of a number are digits that possess certain meaning .
It includes all digits except: zeros
Rules to find significant figures
1.All non-zero digits are considered significant. For example, 23 has two significant figures.
2.Zeros in between two non-zero digits are significant: like in 202.1201 has seven significant figures.
3.Zeros to the left of the significant figures are not significant. For example, .000021 has two significant figures, zeros have no value .
4.Zeros to the right of the significant figures are significant.
That is the reason in number 5060 , it has 3 significant figures .
Fishes yes according to the age, reptiles yes