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4 years ago

Which of the following forms a new substance? melting, evaporating, freezing or burning

Chemistry

2 answers:

Alekssandra [29.7K]4 years ago

7 0

Answer:

burning

Explanation:

Burning or combustion is a chemical change. Hydrocarbon in the presence of oxygen burns to form carbon dioxide and water. In chemical change reactants react with one another to form new products. In chemical change the chemical composition and chemical property of the reactants and products and different from each other.

In a physical change there is only a change in the phase of the substance no new substance is formed. Melting, evaporating, freezing are all phase changes hence they are all physical changes.

Slav-nsk [51]4 years ago

4 0

It would be burning be cause when you freeze, evaporate, or melt anything it is just changing how fast the atoms are moving . Think of it like water, ice, and steam, they are all the same thing but in different forms because of melting, evaporating,and melting. Burning is breaking it down.

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We can change a gas to liquid by _____ the temperature and ______ the pressure.

mina [271]

Decreasing incresing

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3 years ago

Hess’s Law can be used to determine the heat of reaction in the lab. True False

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I think it's false I'm just guessing

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3 years ago

If you fill your car tire to a pressure of 32 psi (pounds per square inch) on a hot summer day when the temperature is 35°C (95°

Murrr4er [49]

By Gay Lussacs law you can find the pressure. First both temperatures of Celsius must change to Kelvin by adding 273. Temperature one will be 308K and temperature 2 will be 258K
With this info, you can now find the pressure with Lussacs law

P1 = P2
— —
T1 T2

Pressure 1 is given which is 32 psi so just plug it all in and find P2

32 = x
—— ——
308 258

308x = 8256 (Cross multiply)

X = 26.8 (divide both sides by 308)

Answer is 26.8 PSI

This makes sense because as temperature increases pressure increases, as well as when temperature decreases, pressure decreases. Since it’s a colder day the pressure will be lower.

4 0

4 years ago

18.2L of gas at 95°C and 760 torr is placed in a 15L container at 80 degrees * C ; what is the new pressure ?

romanna [79]

Answer:

884.56 torr

Explanation:

Formula: $\frac{P_{1}V_{1} }{T_{1}} = \frac{P_{2}V_{2} }{T_{2}}$

P = Pressure

V = Volume

T = Temperature in kelvin (Celsius + 273.15)

$\frac{(760)(18.2) }{368.15} = \frac{P(15) }{353.15}$

$P = \frac{(760)(18.2)(353.15) }{(368.15)(15)}$

P = 884.56169

4 0

3 years ago

3. Given 20g of Barium Hydroxide, how many grams of

anastassius [24]

The number of grams of ammonium nitrate (NH₄NO₃) it would take for all the barium hydroxide to react is 18.7g

First, we will write the balanced chemical equation for the reaction

The balanced chemical equation for the reaction is

Ba(OH)₂ + 2NH₄NO₃ → 2NH₄OH + Ba(NO₃)₂

This means, 1 mole of barium hydroxide is required to react with 2 moles of ammonium nitrate

Now, we will calculate the number of moles of barium hydroxide present.

Mass of barium hydroxide (Ba(OH)₂) = 20 g

Using the formula

$Number\ of\ moles = \frac{Mass}{Molar\ mass}$

Molar mass of Ba(OH)₂ = 171.34 g/mol

∴ Number of moles of Ba(OH)₂ present = $\frac{20}{171.34}$

Number of moles of Ba(OH)₂ present = 0.116727 mole

Now,

Since 1 mole of barium hydroxide is required to react with 2 moles of ammonium nitrate

Then,

0.116727 mole of barium hydroxide will react with 2 × 0.116727 mole of ammonium nitrate

2 × 0.116727 = 0.233454 mole

∴ Number of moles of NH₄NO₃ required is 0.233454 mole

Now, for the mass of ammonium nitrate (NH₄NO₃) required

From the formula

Mass = Number of moles × Molar mass

Molar mass of NH₄NO₃ = 80.043 g/mol

∴ Mass of NH₄NO₃ required = 0.233454 × 80.043

Mass of NH₄NO₃ required = 18.68636 g

Mass of NH₄NO₃ required ≅ 18.7g

Hence, the number of grams of ammonium nitrate (NH₄NO₃) it would take for all the barium hydroxide to react is 18.7g

Learn more on determining mass of reactant required here: brainly.com/question/11232389

6 0

2 years ago