A is correct. Potential energy decreases and turns into kinetic energy.
Answer:
Xm ethylene glycol = 0.16
Molality = 10.75 m
Molarity = 11.3M
Explanation:
40.0% by mass. This data says that 40 g of ethyelen glycol are contained in 100 g of solution
Therefore: Mass of solute is 40g
Mass of solvent = 60 g
Mass of solution = 100 g
We convert the mass to moles → 40 g . 1mol / 62 g = 0.645 moles
We convert the solvent mass to moles → 60 g . 1mol /18g = 3.33 moles
Xm ethylene glycol = Moles of ethylene glycol / Total moles
0.645 / (0.645 + 3.33) = 0.16
Molality are the moles of solute in 1kg of solvent.
We convert the mass of solvent to kg → 60 g . 1kg/1000g = 0.060kg
Molality (mol/kg) = 0.645 mol /0.060kg = 10.75 m
To determine molarity we use the density of solution in order to find out the volume: density = mass / volume
1.75 g/cm³ = 100 g / volume → 100 g / 1.75 g/cm³ = 57.1 cm³ (1cm³ = 1ml)
We convert the solution's volume to L → 57.1 mL . 1L/1000mL = 0.0571L
Molarity → moles of solute in 1L of solution
Molarity (mol/L) → 0.645 mol / 0.0571L = 11.3M
Answer:
166 torr
Explanation:
Let’s call ethane Component 1 and propane Component 2.
According to Raoult’s Law,
where
p₁ and p₂ are the vapour pressures of the components above the solution
χ₁ and χ₂ are the mole fractions of the components
p₁° and p₂° are the vapour pressures of the pure components.
Data:
p₁° = 304 torr
p₂° = 27 torr
n₁ = n₂
1. Calculate the mole fraction of each component
χ₁ = n₁/(n₁ + n₂)
χ₁ = n₁/n₁ + n₁)
χ₁ = n₁/(2n₁)
χ₁ = ½
χ₁ = 0.0.5
χ₂ = 1- χ₁ = 1- 0.5 = 0.5
2. Calculate the vapour pressure of the mixture
Answer:
The atomic number is the number of protons in the nucleus and also the number of orbiting electrons. The mass number is the number of protons and neutrons in the nucleus.
The mass number minus the atomic number is the number of neutrons in the nucleus.
An isotope will have a different atomic mass.
<span>These are five questions and five answers.
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</span><span>1. A substance that can be separated into two or more substances only by a chemical change is a.</span><span /><span />
<span>Answer: compound
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<span>Explanation:
</span><span />
<span>i) solution is a homogenous mixture and it can be separated by physical media. For example, a brine: you can evaporate the water from the salt by heating the solution (brine)
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<span>ii) elements cannot be separated into two or more substances except by nuclear reactions.
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<span>iii) mixtures: heterogenous and homogenous mixtures can be separated by physical treatments.
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<span>iv) compounds are substaces composed of different elements bonded chemically; only chemical reactions break the chemical bonds or create new chemical bonds leading a compound to form other substances.
2. Which of the following materials is a substance?
</span><span />
<span>Answer: silver
</span><span />
<span>Explanation:
</span><span>
</span><span>Substances have a definite composition that can only be modified by chemical reactions.
</span><span>
</span><span>
</span><span>Elements and compounds are substances.
</span><span>
</span><span>
</span><span>Silver is an element, such as sodium, gold, oxygen. You can find the list of the 118 known elements in a periodic table.
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</span><span>Mixtures, either homogenous or heterogeneous, can be separated by physical mechanisms and so they are not substances: air, gasoline, and stainless steel are mixtures because they have not a unique chemical formula but are formed by other compounds or elements in different proportions, i.e. with not a unique chemical formula.</span><span /><span>
3.The first figure in a properly written chemical symbol always is _____.
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<span>Answer: capitalized
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<span>Explanation:
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</span><span>This is a rule to write the symbols of the elements. For example, Na (sodium), Br (bromine), I (iodine), O (oxygen), Ne (neon).</span><span /><span>
4. Which of the following represents a compound?
Answer: H2O
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</span><span>Explanation:
</span><span>
</span><span>
</span><span>That is the only chemical formula. The other representations are not valid chemical formulas. A chemical cormula can oly contain chemical symbols and subscript numbers, to represent the kind of atoms (elements) and how many of each (the subscrip).</span><span /><span>
5. What do chemical symbols and formulas represent, respectively?
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<span>Answer: elements and compounds
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<span>Justification:
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<span>1) The symbols are used to represnt elements, such as Na (sodium), Li (lithium), Be (berylium)
2) Chemical formulas represent compunds. For example: CO is carbon monoxide, CO2 is carbon dioxide, H2CO3 is carbonic acid, Na2CO3 is sodium carbonate.
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<span>Each compound has a unique chemical formula.
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