All categories

3 years ago

Which of the following is a sign a chemical reaction has occurred?

Chemistry

2 answers:

tankabanditka [31]3 years ago

6 0

A solid dissolves in abolishing forms from the mixing of 2 liquids

dimulka [17.4K]3 years ago

6 0

Answer: A solid forms when two liquids are mixed.

Explanation:

A physical reaction is defined as the reaction in which a change in shape, size takes place. No new substance gets formed in these reactions.

A chemical reaction is defined as the reaction in which a change in chemical composition takes place. A new substance is formed in these reactions.

1. A solid dissolves in liquid: Only the phase of the solid changes to aqueous and no new substance is formed, thus is a physical change.

2. A solid forms when two liquids are mixed: two liquids can forma solid only on chemical combination and formation of new substance.

3. A solid melts to a liquid when it is heated: Only the phase of the solid changes to liquid, no new substance is formed, thus is a physical change.

4. A solid metal changes shape: Only the shape of the solid changes, thus is a physical change.

You might be interested in

Draw a formula for Thr-Gly-Ala (T-G-A) in its predominant ionic form at pH 7.3. You may assume for the purposes of this question

Rudiy27

Answer:

gggggggggg

Explanation:

gggggggg

8 0

2 years ago

Pressure gauge at the top of a vertical oil well registers 140 bars. The oil well is 6000 m deep and filled with natural gas dow

andreyandreev [35.5K]

Explanation:

(a) The given data is as follows.

Pressure on top ( $P_{o}$ ) = 140 bar = $1.4 \times 10^{7} Pa$ (as 1 bar = $10^{5}$ )

Temperature = $15^{o}C$ = (15 + 273) K = 288 K

Density of gas = $\frac{PM}{ZRT}$

$\frac{dP}{dZ} = \rho \times g$

$\frac{dP}{dZ} = \int \frac{PM}{ZRT}$

$\int_{P_{o}}^{P_{1}} \frac{dP}{dZ} = \frac{Mg}{ZRT} \int_{0}^{4700} dZ$

$ln (\frac{P_{1}}{P_{o}}) = \frac{18.9 \times 10^{-3} \times 9.81 \times 4700 m}{0.80 \times 8.314 J/mol K \times 288 K}$

= 0.4548

$P_{1} = P_{o} \times e^{0.4548}$

= $1.4 \times 10^{7} Pa \times 1.5797$

= $2.206 \times 10^{7} Pa$

Hence, pressure at the natural gas-oil interface is $2.206 \times 10^{7} Pa$ .

(b) At the bottom of the tank,

$P_{2} = P_{1} + \rho \times g \times h$

= 2.206 \times 10^{7} Pa + 700 \times 9.81 \times (6000 - 4700)[/tex]

= $309.8 \times 10^{5} Pa$

= 309.8 bar

Hence, at the bottom of the well at $15^{o}C$ pressure is 309.8 bar.

6 0

3 years ago

Explain with example, why there cannot be an oxidation reaction without a corresponding reduction reaction

Vlada [557]

Because matter cannot be created or destroyed

8 0

2 years ago

Read 2 more answers

Consider the heating curve for water. A graph of the heating curve for water has time in minutes on the horizontal axis and Temp

Zolol [24]

Answer:

0°C.

Explanation:

Hello,

In this case, given the heating curve of water on the attached document, we can notice that at 0 °C the solid starts melting, which means that the melting point is reached. Melting point is known as a physical change whereby a solid changes to liquid by the addition of heat as it allows the molecules to separate to each other.

Best regards.

4 0

3 years ago

All molecules have the same kinetic energy and hence the same speed.<br><br> O True<br><br> O False

topjm [15]

False...their speed differs

4 0

2 years ago