Which of the following shows the 3 main jobs of a cell?

Is ice melting in a drink a chemical change?

konstantin123 [22]

Nope, it's a physical change. When ice melts it changes into liquid water, it's still water. Changes in which no new substances are formed are physical changes, hence this is a physical change.

6 0

4 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

Which one of the following descriptions relating to nuclear reactions is correct?

monitta

Answer: option D - The total number of nucleons changes.

Explanation:

Nuclear Reaction is best described as a process such as the fission of an atomic nucleus, or the fusion of one or more atomic nuclei and / or subatomic particles in which the NUMBER of PROTONS and / or NEUTRONS in a nucleus CHANGES; the reaction products may contain a different element or a different isotope of the same element.

Note that the NUCLEONS refers to ONE of the subatomic particles of the atomic nucleus, i.e. a PROTON or a NEUTRON.

So, in a Nuclear reaction, the total number of nucleons changes.

4 0

3 years ago

PLS HELPPP why is CH3OH more polar than CH3CH2OH

dusya [7]

Answer:

Explanation:

Polarity is about differencens in electronegativity. CH bonds have around the same electronegativity value so a CH bond is nonpolar. The more CH bonds there are in a molecule, the more nonpolar it is. Since CH3CH2OH has more carbon-hydrogen bonds than CH3OH, it is more nonpolar. With the same reasoning, since CH3OH has less CH bonds, it's more polar.

8 0

3 years ago

A gas at 928 kpa, 129 C occupies a volume of 569 L. Calculate the volume at 319 kpa and 32 C.

lisabon 2012 [21]

Answer:

1255.4L

Explanation:

Given parameters:

P₁ = 928kpa

T₁ = 129°C

V₁ = 569L

P₂ = 319kpa

T₂ = 32°C

Unknown:

V₂ = ?

Solution:

The combined gas law application to this problem can help us solve it. It is mathematically expressed as;

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

P, V and T are pressure, volume and temperature

where 1 and 2 are initial and final states.

Now,

take the units to the appropriate ones;

kpa to atm, °C to K

P₂ = 319kpa in atm gives 3.15atm

P₁ = 928kpa gives 9.16atm

T₂ = 32°C gives 273 + 32 = 305K

T₁ = 129°C gives 129 + 273 = 402K

Input the values in the equation and solve for V₂;

$\frac{9.16 x 569}{402} = \frac{3.15 x V_{2} }{305}$

V₂ = 1255.4L

4 0

3 years ago