Which method is the first step when scientists communicate their scientific results?

Describe endothermic vs. exothermic reactions in terms of product formation. (hint: what happens when products are formed?)

shusha [124]

Answer:

Endothermic reaction chemical equation

Reactnt A + Reactant B + Heat (energy) ⇒ Products

Exothermic reaction chemical equation

Reactnt A + Reactant B ⇒ Products + Heat (energy)

Explanation:

Endothermic Reaction

An endothermic reaction is a reaction that reaction that requires heat before it would take place resulting in the absorption of heat from the surrounding that can be sensed by the coolness of the reacting system

An example of an endothermic reaction is a chemical cold pack that becomes cold when the chemical and water inside it reacts

Exothermic Reaction

An exothermic reaction is one that rekeases energy to the surroundings when it takes place. This is as a result of the fact that the combined heat energy of the reactants is more than the chemical heat energy of the products. An example of an exothermic reaction is a burning candle

5 0

2 years ago

blood plasma for average adults has a volume of 3100mL. if the density of plasma is 1.020 g/mL, what mass of plasma is in the av

Gnoma [55]

Answer:

The volume of blood plasma in adults is 3.1 L. it's density is 1.03 g/cm3.

Explanation:

4 0

2 years ago

In the laboratory, a general chemistry student measured the pH of a 0.529 M aqueous solution of phenol (a weak acid), C6H5OH to

Artyom0805 [142]

Answer:

The dissociation constant of phenol from given information is $9.34\times 10^{-11}$ .

Explanation:

The measured pH of the solution = 5.153

$C_6H_5OH\rightarrow C_6H_5O^-+H^+$

Initially c

At eq'm c-x x x

The expression of dissociation constant is given as:

$K_a=\frac{[C_6H_5O^-][H^+]}{[C_6H_5OOH]}$

Concentration of phenoxide ions and hydrogen ions are equal to x.

$pH=-\log[x]$

$5.153=-\log[x]$

$x=7.03\times 10^{-6} M$

$K_a=\frac{x\times x}{(c-x)}=\frac{x^2}{(c-x)}=\frac{(7.03\times 10^{-6} M)^2}{ 0.529 M-7.03\times 10^{-6} M}$

$K_a=9.34\times 10^{-11}$

The dissociation constant of phenol from given information is $9.34\times 10^{-11}$ .

4 0

2 years ago

Under certain conditions Argon gas diffuses at a rate of 3.2 cm per second under the same conditions an unknown gas diffuses at

kozerog [31]

Answer:

20 g/mol

Explanation:

We can use Graham’s Law of diffusion:

The rate of diffusion (r) of a gas is inversely proportional to the square root of its molar mass (M).

$r = \frac{1 }{\sqrt{M}}$

If you have two gases, the ratio of their rates of diffusion is

$\frac{r_{2}}{r_{1}} = \sqrt{\frac{M_{1}}{M_{2}}}$

Squaring both sides, we get

$(\frac{r_{2}}{r_{1}})^{2} = \frac{M_{1}}{M_{2}}$

Solve for M₂:

$M_{2} = M_{1} \times (\frac{r_{1}}{r_{2}})^{2}$

$M_{2} = \text{39.95 g/mol} \times (\frac{\text{3.2 cm/s}}{\text{4.5 cm/s}})^{2}= \text{39.95 g/mol} \times (0.711 )^{2}$

$= \text{39.95 g/mol} \times 0.506 = \textbf{20 g/mol}$

7 0

2 years ago

How are water-based solutions formed?

drek231 [11]

Answer:

D. Solutions are formed when the water’s polar molecules separate the polar molecules of an ionic or molecular compound.

Explanation:

Solutions are homogeneous mixtures formed by interaction between solutes and solvents.

Water based solutions have water as the solvents and mostly ionic and molecular compounds as their solutes.

Water is a polar solvent that is capable of dissolving many compounds by hydrating them. The molecules of water surrounds the solute and forces them to separate.

6 0

2 years ago