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3 years ago

A teacher wants to perform a classroom demonstration that illustrates both chemical and physical changes. Which

Chemistry

2 answers:

wariber [46]3 years ago

5 0

It would be dissolving sugar in water/burning a candle

NeX [460]3 years ago

3 0

Answer:

dissolving sugar in water

burning a candle

Explanation: these both have chemical and physical changes happening to them.

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How many moles are in 17.2g k2s

Natalija [7]

Answer: 0.156 mol

Explanation:

To find the moles of 17.2 g K₂S, we need to know the molar mass to convert.

$17.2g*\frac{mol}{110.256 g} =0.156 mol$

3 0

3 years ago

In an aqueous chloride solution cobalt(ii) exists in equilibrium with the complex ion cocl42-. co2 (aq) is pink and cocl42-(aq)

liraira [26]

First you should know that the Principle of Le Chatelier states that if a system in equilibrium is subjected to a change of conditions, it will move to a new position in order to counteract the effect that disturbed it and recover the state of equilibrium.

The variation of one or several of the following factors can alter the equilibrium condition in a chemical reaction:

Temperature
The pressure
The volume
The concentration of reactants or products

1. This reaction is: a. exothermic

The chemical equilibrium at issue is:

CoCl₄²⁻ ⇄ Co²⁺ + 4Cl⁻ + heat

blue pink

The reaction of the question is exothermic because when adding heat (at high temperature) the equilibrium moves to the left since the blue color is strong which means that there are more reagent (CoCl₄²⁻) that product (Co²⁺). On the other hand, when extracting heat from the system (at low temperature) the equilibrium moves to the right since the pink color predominates and more product is present in the solution.

2. When the temperature is decreased the equilibrium constant, k: c. remains the same.

As mentioned above, a system in equilibrium that is disturbed will move to a new position in order to counteract the effect that disturbed it and recover the state of equilibrium. In this way, the system will always remain in equilibrium and its equilibrium constant will remain constant. This is why, despite altering the temperature of the system, the equilibrium constant remains constant.

3. When the temperature is decreased the equilibrium concentration of Co²⁺: a. increases

Again, the chemical equilibrium at issue is:

CoCl₄²⁻ ⇄ Co²⁺ + 4Cl⁻ + heat

As the reaction in question is exothermic when the temperature decreases, heat is extracted from the system. To compensate this decrease in heat, the system will react by shifting the balance to the right, increasing the concentration of the products and, therefore, the concentration of Co²⁺.

5 0

4 years ago

Write a journal entry from the perspective of a particle of light, called a photon. Your story should follow the photon as it tr

nata0808 [166]

Answer:

Astronomy (from Greek: ἀστρονομία, literally meaning the science that studies the laws of the stars) is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole.[1]

Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonians, Greeks, Indians, Egyptians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars. Nowadays, professional astronomy is often said to be the same as astrophysics.[2]

Professional astronomy is split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects. This data is then analyzed using basic principles of physics. Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. These two fields complement each other. Theoretical astronomy seeks to explain observational results and observations are used to confirm theoretical results.

Astronomy is one of the few sciences in which amateurs play an active role. This is especially true for the discovery and observation of transient events. Amateur astronomers have helped with many important discoveries, such as finding new comets.

Explanation:

7 0

2 years ago

Most elements are O non metals O metalloids O metals O gases

Aliun [14]

Metallioids
Explain

4 0

3 years ago

How many types of alkanol do we have

oksano4ka [1.4K]

I think you mean alcohol ? if so there are a few basic types including ethanol

6 0

3 years ago