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2 years ago

Which of the following would violate laboratory safety rules? (1 point)

Chemistry

1 answer:

mixer [17]2 years ago

5 0

Answer:

wearing open toed shoes

Explanation:

this is because you could drop said chemicals and hurt yourself unless you are where some cover on your feet.

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Méthode pour sépare l'eau et vermiculite !

wolverine [178]

Answer:

Filtración

Explanation:

Cuando se filtra una mezcla de arena y agua, la vermiculita se queda en el papel de filtro y el agua gotea. Como un filtro de café.

8 0

3 years ago

A weather balloon is filled with helium that occupies a volume of 5.57 104 L at 0.995 atm and 32.0°C. After it is released, it r

Alchen [17]

6.52 × 10⁴ L. (3 sig. fig.)

<h3>Explanation</h3>

Helium is a noble gas. The interaction between two helium molecules is rather weak, which makes the gas rather "ideal."

Consider the ideal gas law:

$P\cdot V = n\cdot R\cdot T$ ,

where

$P$ is the pressure of the gas,
$V$ is the volume of the gas,
$n$ is the number of gas particles in the gas,
$R$ is the ideal gas constant, and
$T$ is the absolute temperature of the gas in degrees Kelvins.

The question is asking for the final volume $V$ of the gas. Rearrange the ideal gas equation for volume:

$V = \dfrac{n \cdot R \cdot T}{P}$ .

Both the temperature of the gas, $T$ , and the pressure on the gas changed in this process. To find the new volume of the gas, change one variable at a time.

Start with the absolute temperature of the gas:

$T_0 = (32.0 + 273.15) \;\text{K} = 305.15\;\text{K}$ ,
$T_1 = (-14.5 + 273.15) \;\text{K} = 258.65\;\text{K}$ .

The volume of the gas is proportional to its temperature if both $n$ and $P$ stay constant.

$n$ won't change unless the balloon leaks, and
consider $P$ to be constant, for calculations that include $T$ .

$V_1 = V_0 \cdot \dfrac{T_1}{T_2} = 5.57\times 10^{4}\;\text{L}\times \dfrac{258.65\;\textbf{K}}{305.15\;\textbf{K}} = 4.72122\times 10^{4}\;\text{L}$ .

Now, keep the temperature at $T_1 =258.65\;\text{K}$ and change the pressure on the gas:

$P_1 = 0.995\;\text{atm}$ ,
$P_2 = 0.720\;\text{atm}$ .

The volume of the gas is proportional to the reciprocal of its absolute temperature $\dfrac{1}{T}$ if both $n$ and $T$ stays constant. In other words,

$V_2 = V_1 \cdot\dfrac{\dfrac{1}{P_2}}{\dfrac{1}{P_1}} = V_1\cdot\dfrac{P_1}{P_2} = 4.72122\times 10^{4}\;\text{L}\times\dfrac{0.995\;\text{atm}}{0.720\;\text{atm}}=6.52\times 10^{4}\;\text{L}$

(3 sig. fig. as in the question.).

See if you get the same result if you hold $T$ constant, change $P$ , and then move on to change $T$ .

6 0

2 years ago

pH indicator. A dye that is an acid and that appears as different colors in its protonated and deprotonated forms can be used as

Vitek1552 [10]

Answer:

pH = 7.8

Explanation:

The Henderson-Hasselbalch equation may be used to solve the problem:

pH = pKa + log([A⁻] / [HA])

The solution of concentration 0.001 M is a formal concentration, which means that it is the sum of the concentrations of the different forms of the acid. In order to find the concentration of the deprotonated form, the following equation is used:

[HA] + [A⁻] = 0.001 M

[A⁻] = 0.001 M - 0.0002 M = 0.0008 M

The values can then be substituted into the Henderson-Hasselbalch equation:

pH = 7.2 + log(0.0008M/0.0002M) = 7.8

7 0

3 years ago

Which shows a correct association between a structure and one of its functions?

Elden [556K]

Answer:

Explanation:

Sweat glands remove waste

5 0

3 years ago

The amount of matter is an object is known as _____.

Licemer1 [7]

Density is the mass of a substance per unit volume. Volume is the amount of space an object occupies.

7 0

3 years ago