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3 years ago

HURRY I WILL GRANT 100 PTS AND BRAINLIEST

Chemistry

1 answer:

Zanzabum3 years ago

4 0

Answer:

Occurs when a scientists expectations change how the results of an experiment are viewed Constant In an experiment, a variable that does not change when other variables change.

Explanation:

A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with the available scientific theories. Even though the words "hypothesis" and "theory" are often used synonymously, a scientific hypothesis is not the same as a scientific theory. A working hypothesis is a provisionally accepted hypothesis proposed for further research, in a process beginning with an educated guess or thought.

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If 45.0 mL of ethanol (density =0.789g/mol) initially at 6.0°C mix with 45.0 mL of water (density =1.0 g/mol) initially at 28.0°

Likurg_2 [28]

The final temperature of the mixture : 21.1° C

<h3>Further explanation </h3>

The law of conservation of energy can be applied to heat changes, i.e. the heat received / absorbed is the same as the heat released

Q in(gained) = Q out(lost)

Heat can be calculated using the formula:

Q = mc∆T

Q = heat, J

m = mass, g

c = specific heat, joules / g ° C

∆T = temperature difference, ° C / K

Q ethanol=Q water

mass ethanol=

$\tt mass=\rho\times V\\\\mass=0.789\times 45=35.505~g$

mass water =

$\tt mass=1~g/ml\times 45~ml=45~g$

then the heat transfer :

$\tt 35.505\times 2.42~J/g^oC\times (t-6)=45\times 4.18~J/g^oC\times (28-t)\\\\85.922t-515.533=5266.8-188.1t\\\\274.022t=5782.33\rightarrow t=21.1^oC$

5 0

3 years ago

A solution

timurjin [86]

The answer to your question is C. A solution is a homogeneous mixture composed of two or more substances, so it couldn't have been A and D. Since a solution can't have its substances separated by a chemical means because they are chemically bonded, thus they are able to be separated by physical means

3 0

3 years ago

A diver exhales a bubble with a volume of 250 mL at a pressure of 2.4 atm and a temperature of 15 °C. What is the volume of the

alexdok [17]

Answer : The volume of the bubble is, 625 mL

Explanation :

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1$ = initial pressure of gas = 2.4 atm

$P_2$ = final pressure of gas = 1.0 atm

$V_1$ = initial volume of gas = 250 mL

$V_2$ = final volume of gas = ?

$T_1$ = initial temperature of gas = $15^oC=273+15=288K$

$T_2$ = final temperature of gas = $27^oC=273+27=300K$

Now put all the given values in the above equation, we get:

$\frac{2.4atm\times 250mL}{288K}=\frac{1.0atm\times V_2}{300K}$

$V_2=625mL$

Therefore, the volume of the bubble is, 625 mL

7 0

3 years ago

Explain Charles law

kodGreya [7K]

"Charles Law" is the relationship between "volume-temperature" (V ∝ T).

<u>Explanation</u>:

Charles Law is basically volume-temperature relationship (V ∝ T). French scientist “Jacques Charles” in 1787 studied effect of temperature on the volume of gases at constant pressure, which described how gases manage to expand when heated. Law stated as “At constant pressure, the volume of a given "mass" of a gas decreases or increases by 1/273 of its volume at $0^{\circ} \mathrm{C}$ for each one degree rise or fall in temperature”. Formula derived from law is as follows: $\mathbf{V}_{\mathbf{t}}=\mathbf{V}_{0}[\mathbf{1}+\mathbf{t} / \mathbf{2} 7 \mathbf{3}]$ here ${V}_{0}$ is volume of given mass of a gas at $0^{\circ} \mathrm{C}$ , ${V}_{t}$ is its volume at any temperature $t^{\circ} \mathrm{C}$ . Application of Charles law is hot air balloons.

8 0

3 years ago

What is chemical reaction?<br>

Aliun [14]

Answer:

a process that involves rearrangement of the molecular or ionic structure of a substance, as distinct from a change in physical form or a nuclear reaction

3 0

3 years ago

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