All categories

4 years ago

What are two ways to tell if a chemical reaction is taking place?

2 answers:

6 0

A chemical reaction is observed by physical effects that cannot be undone, for Ex. If an object give off heat or light, thats a chemical reaction. If theirs a change in an objects color it can be a chemical reaction, like rust. Metal turning silver to brown. <span />

Kruka [31]4 years ago

4 0

1) temperature change
2)odor or smell change
Hope this helps

You might be interested in

Calculate ΔrG∘ at 298 K for the following reactions.CO(g)+H2O(g)→H2(g)+CO2(g)2-Predict the effect on ΔrG∘ of lowering the temper

KonstantinChe [14]

Answer:

1) ΔG°r(298 K) = - 28.619 KJ/mol

2) ΔG°r will decrease with decreasing temperature

Explanation:

CO(g) + H2O(g) → H2(g) + CO2(g)

1) ΔG°r = ∑νiΔG°f,i

⇒ ΔG°r(298 K) = ΔG°CO2(g) + ΔG°H2(g) - ΔG°H2O(g) - ΔG°CO(g)

from literature, T = 298 K:

∴ ΔG°CO2(g) = - 394.359 KJ/mol

∴ ΔG°CO(g) = - 137.152 KJ/mol

∴ ΔG°H2(g) = 0 KJ/mol........pure substance

∴ ΔG°H2O(g) = - 228.588 KJ/mol

⇒ ΔG°r(298 K) = - 394.359 KJ/mol + 0 KJ/mol - ( - 228.588 KJ/mol ) - ( - 137.152 KJ7mol )

⇒ ΔG°r(298 K) = - 28.619 KJ/mol

2) K = e∧(-ΔG°/RT)

∴ R = 8.314 E-3 KJ/K.mol

∴ T = 298 K

⇒ K = e∧(-28.619/(8.314 E-3)(298) = 9.624 E-6

⇒ ΔG°r = - RTLnK

If T (↓) ⇒ ΔG°r (↓)

assuming T = 200 K

⇒ ΔG°r(200 K) = - (8.314 E-3)(200)Ln(9.624E-3)

⇒ ΔG°r (200K) = - 19.207 KJ/mol < ΔG°r(298 K) = - 28.619 KJ/mol

6 0

3 years ago

You have decided to test the effects of five garden fertilizers by applying some of each to five separate rows of radishes. what

attashe74 [19]

You are testing which fertilizer makes the radishes grow the fastest.

factors you should control: sunlight exposure, water amount, fertilizer amount.

Measure: check the rows of radishes to see how much each row has grown in comparison to the others. Whichever row with the healthiest radishes has the best fertilizer.

5 0

3 years ago

Metals have high melting and boiling points and are often shiny and silvery. Which of the blocks are metals?

DanielleElmas [232]

Answer:

S and p blocks elements are considered metals while d-block elements are considered transition metals.

Explanation:

s-block consist of lithium, sodium, potassium, rubidium, cesium and francium metals.

All are these called alkali metals.

These metals have one valance electron.

These metals are soft and having low density.

They easily lose their one valance electron and form cation with +1 charge.

They have low melting points.

P- block elements includes beryllium, magnesium, calcium, strontium, barium, radium metals.

They are called alkaline earth metals.

All are these have two valance electrons.

They easily lose their valance electrons and form cation with charge of +2.

These metals are also very soft.

They form salt with halogens.

They are also very reactive metals.

8 0

3 years ago

Can anyone help me out with these questions

Rus_ich [418]

Answer:

2. B It is the outermost layer of Earth, composed of solid rock and divided into sections called plates. 3. B The inner core is kept solid by the intense pressure of all the layers above it.

Explanation:

5 0

3 years ago

Which process is an example of a chemical change?

Ivanshal [37]

A metal rail rusting in damp weather.

8 0

3 years ago

Read 2 more answers