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3 years ago

What must ALWAYS be used to convert between quantities of two different chemical substances?

Chemistry

2 answers:

valentinak56 [21]3 years ago

8 0

Answer:

ask your mom and your family

Explanation:

tell your mom that she sucks

Vedmedyk [2.9K]3 years ago

3 0

Answer:

Balanced equations and mole ratios

In general, mole ratios can be used to convert between amounts of any two substances involved in a chemical reaction.

Explanation:

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Chlorofluorocarbons (CFCs) are no longer used as refrigerants because they destroy the ozone layer. Trichlorofluoromethane (CCl₃

Daniel [21]

Answer:

The molar entropy of the evaporation of Trichlorofluoromethan is 83.516 J/molK.

Explanation:

Entropy :It is defined as amount of energy which is unable to do work or the measurement of randomness or disorderedness in a system.

$S=\frac{Q}{T(Kelvins)}$

Molar heat of molar vaporization of Trichlorofluoromethane = 24.8 kJ/mol

Temperature at which Trichlorofluoromethan boils , T= 296.95 K

The molar entropy of the evaporation of Trichlorofluoromethan :

$=\frac{24.8 kJ/mol}{296.95 K}=0.083516 kJ/mol K = 83.516 J/molK$

The molar entropy of the evaporation of Trichlorofluoromethan is 83.516 J/molK.

8 0

3 years ago

Vinegar is classified as a base, acid, or is it neutral ?

Scrat [10]

Answer:

Vinegar is acidic => acetic acid (HC₂H₃O₂)

Explanation:

Vinegar consists of acetic acid (HC₂H₃O₂), water and trace amounts of other chemicals, which may include flavorings. The concentration of the acetic acid is variable. Distilled vinegar contains 5-8% acetic acid.

7 0

3 years ago

Which of the following statements is incorrect? A. Molecular mass is expressed in atomic mass units. B. Formula mass compares th

n200080 [17]

Answer:

The incorrect statement is the choice C. Atomic mass has units of grams per atom.

Explanation:

1) Choice A. Molecular mass is expressed in atomic mass units.

Correct. Atomic mass units (a.m.u) is the standard unit used to express the mass of the atoms and the molecules.

Since, one atom, molecule, or formula unit is a tiny amount of material, it has a ver, very low mass, and the unit mass of a molecule is referred to one mole (6.022 × 10²³ units).

2) Choice B. Formula mass compares the mass of one formula unit of a substance to the mass of one atom of carbon-12.

Correct. The masses of atoms and compounds are referred to a standard. Such standard is the carbon-12 atom. This is, the cabon-12 atom was selected as the standard and its exact mass is 12 a.m.u.

3) Choice C. Atomic mass has units of grams per atom.

Incorrect. Atomic mass is the mass of the atoms, but, since, the mass of one atom is so small, the atomic mass is referred to one mole. Hence, the atomic mass has units of grams per mole.

4) Choice D. Both molecular mass and formula mass use carbon-12 as a reference standard.

Correct. As stated when explaining the option B, the mass of atoms, molecules, and formula units are referred to carbon-12 standard.

5) Choice E. Sodium chloride, an ionic compound, is said to have a formula weight, but not a molecular weight.

Correct. The reason is that ionic compounds form large structures (crystals) and, since there is not such thing as one molecule of them, they are said to have formula weight (or mass) but not a molecular weight.

The name molecules is reserved for covalent compounds, where you can formally identify molecules. E.g. Water is a molecular compound, and each molecule has molecular formula H₂O, whose mass is the molecular mass.

7 0

3 years ago

What is the half-life of a pharmaceutical if the initial dose is 500 mg and only 31 mg remains after 6 hours?

Sergeu [11.5K]

Answer:

$\large \boxed{\text{b. 1.5 h}}$

Explanation:

1. Calculate the rate constant

The integrated rate law for first order decay is

$\ln \left (\dfrac{A_{0}}{A_{t}}\right ) = kt$

where

A₀ and A_t are the amounts at t = 0 and t

k is the rate constant

$\begin{array}{rcl}\ln \left (\dfrac{500}{31}\right) & = & k \times 6\\\\\ln 16.1 & = & 6k\\2.78& =& 6k\\k & = & \dfrac{2.78}{6}\\\\& = & 0.463 \text{ h}^{-1}\\\end{array}$

2. Calculate the half-life

$t_{\frac{1}{2}} = \dfrac{\ln2}{k} = \dfrac{\ln2}{\text{0.463 h}^{-1}} = \textbf{1.5 h}\\\\ \text{The half-life is $\large \boxed{\textbf{1.5 h}}$}$

4 0

3 years ago

Help please you don’t need to show work

aleksandrvk [35]

Answer:

24.07

Explanation:

6 0

3 years ago