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3 years ago

Sharping a pencil leaves behind pencil shavings. Is sharpening pencil a physical or chemical change

Chemistry

1 answer:

Deffense [45]3 years ago

6 0

Physical, since you are physically changing its appearance

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Which system includes feet, pounds, gallons, and miles? metric customary

slavikrds [6]

Answer:

customary Is the required system

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2 years ago

1.- Ilumina de amarillo los verbos en pretérito y de verde los verbos en copretérito.

ivanzaharov [21]

Answer:

Pretérito (Pretérito perfecto):

estiró, sudó, peleó, compartí

Copretérito (Pretérito imperfecto):

saludaba, pedias, leia, compraba, barrias, cargaba, estrenabas, escribian

Explanation:

Los verbos en pretérito, también llamado pretérito perfecto, son los siguientes:

estiró, sudó, peleó, compartí

Como se aprecia, los verbos conjugados en pretérito perfecto terminan la última sílaba en vocal con acento, es decir, -á, -é, -í u -ó.

Los verbos en copretérito, también llamado pretérito imperfecto, son los siguientes:

saludaba, pedias, leia, compraba, barrias, cargaba, estrenabas, escribian

Como se aprecia, los verbos conjugados en pretérito imperfecto terminan la última sílaba en -ía, ías, -ían, -aba, -abas o -aban.

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3 years ago

An aqueous solution contains 32.7% KCl (wt/wt%). what is the mole fraction of KCl in the solution

inna [77]

The mole fraction of KCl in the solution is 0.1051

calculation

mole fraction of KCl in solution = moles of KCl / total number of moles(moles of KCl +moles of H2O)

moles=mass/molar mass

mass of KCl=32.7g

molar mass of KCl= 39 +35.5

moles of KCl is therefore= 32.7g/74.5 g/mol=0.439 moles

find the moles of H2O= mass of H2O/molar mass

mass of H2O=100-32.7=67.3g

molar mass of H2O=( 1 x2) +16=18 g/mol

moles = 67.3/18 =3.739 moles

total moles=3.739+0.439=4.178 moles

mole fraction is therefore=0.439/4.178=0.1051

5 0

3 years ago

What is the minimum temperature for hot water when using

kirill [66]

Answer:

171°F is the answer of this question

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2 years ago

Aniline is produced by the hydrogenation of nitrobenzene. a small amount of cyclo-hexylamine is produced as a byproduct. the rea

Tom [10]

Aniline can be produced from nitro-benzene by reduction. When nitro-benzene reacts with tin (Sn) + hydrochloride acid (HCl) then aniline is produced. The Sn + HCl forms free hydrogen ions which converts the nitro group of the benzene ring to amine group, which is aniline. In place of Sn + HCl. One can use palladium (Pd) hydrogen mixture in presence of ethanol (EtOH). There produces a side product in this reaction which is cyclohexyl amine. The reaction can be shown as.

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3 years ago