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11 days ago

Which procedure cannot be performed on a hot plate, requiring a Bunsen burner instead

Chemistry

1 answer:

Tems11 [846]11 days ago

4 0

Answer: The process of heating a crucible to eliminate moisture from a hydrate.

Explanation:

The available choices are:

a. Heating a solvent to aid in the dissolution of a solute.

b. Heating a solid in isolation to remove moisture.

c. Bringing water to a boil for use in a water bath.

d. Heating a crucible to eliminate moisture from a hydrate.

Possible actions that can be done on a hot plate include:

a. Heating a solvent to assist a solute in dissolving.

b. Heating a solid in isolation to dry it.

c. Heating water to boiling for a water bath.

However, it's important to note that using a hot plate for heating a crucible to remove water from a hydrate is not advisable. Silica or ceramic materials are not meant to be heated on a hot plate.

Consequently, the correct procedure is heating a crucible to remove water from a hydrate.

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Hitesh wants to learn swimming. He brought swimming costumes and a cap. What kind of material should these be made of and why?

alisha [964]

Answer:

Nylon and Spandex (Lycra).

Explanation:

These materials are designed to fit the body, with nylon drying more quickly than other types of fabrics, and Spandex being commonly found in swimming and sports apparel due to its elastic qualities. Both fabrics also wick moisture away and dry rapidly.

With high capacity and enhanced flexibility, nylon and Spandex provide a snug fit to the body and can retain their shape during various activities, making them ideal for swimming.

This explains why these materials are suitable based on the situation given.

3 0

13 days ago

The speed of light in a vacuum is 2.998 × 10 8 8 m/s. How long does it take for light to circumnavigate the Earth, which has a c

castortr0y [923]

Answer:- 0.134 seconds

Solution:- The speed is given as $2.988*10^8\frac{m}{s}$ and the circumference is 24900 miles which is same as the distance light have to covered. It asks to calculate the time required to cover this distance by the light.

Unit conversion is needed from miles to meters since the speed is given in meters per second.

1 mile = 1609.34 meters

Thus, $24900mile(\frac{1609.34meter}{mile})$

= 40072566 meters

Now, $speed=\frac{distance}{time}$

Rearranged for time, that gives: $time=\frac{distance}{speed}$

Inserting the values:

$time=\frac{40072566meter}{2.988*10^8\frac{meter}{second}}$

= 0.134 seconds

Hence, light would take 0.134 seconds to traverse the indicated distance. The answer without the unit is 0.134.

8 0

4 days ago

Valproic acid, used to treat seizures and bipolar disorder, is composed of C, H, and O. A 0.165-g sample is combusted to produce

VMariaS [1037]

Answer:

The empirical formula is = $C_4H_8O$

The Valproic acid formula is = $C_8H_{16}O_2$

Explanation:

Mass of the produced water = 0.166 g

Molar mass of water = 18 g/mol

The moles of $H_2O$ are calculated as 0.166 g /18 g/mol = 0.00922 moles.

In 1 mole of water, there are 2 moles of hydrogen atoms.

Thus,

Moles of H = 2 x 0.00922 = 0.01844 moles

Each hydrogen atom's molar mass is 1.008 g/mol.

Hydrogen mass in the molecule = 0.01844 x 1.008 = 0.018588 g

Mass of produced carbon dioxide = 0.403 g

Molar mass of carbon dioxide = 44.01 g/mol

The moles of $CO_2$ are calculated as 0.403 g /44.01 g/mol = 0.009157 moles.

Each carbon atom's presence is 1 mole in 1 mole of carbon dioxide.

So,

Moles of C = 0.009157 moles

The molar mass of carbon is 12.0107 g/mol.

Carbon mass in molecule = 0.009157 x 12.0107 = 0.11 g

Since Valproic acid comprises only hydrogen, oxygen, and carbon, the oxygen mass in the sample = Total mass - Carbon mass - Hydrogen mass.

The sample's overall mass = 0.165 g.

Oxygen mass in the sample = 0.165 - 0.11 - 0.018588 = 0.036412 g

The molar mass of oxygen is 15.999 g/mol.

Moles of O = 0.036412 / 15.999 = 0.002276 moles

Taking the simplest ratio for H, O, and C yields:

0.01844: 0.002276: 0.009157

= 8: 1: 4

The empirical formula becomes $C_4H_8O$

While molecular formulas detail the precise count of atoms for each element, empirical formulas represent the simplest form or reduced ratio of these elements in the compound.

Consequently,

The molecular mass equals n × Empirical mass.

Here, n is a positive integer from 1, 2, 3...

Empirical mass = 4×12 + 8×1 + 16 = 72 g/mol.

Molar mass = 144 g/mol.

Thus,

The molecular mass = n × Empirical mass.

144 = n × 72

⇒ n = 2

The Valproic acid formula is = $C_8H_{16}O_2$

7 0

7 days ago

For which applications would you choose a liquid over a gas or solid?

Alekssandra [968]

Solution:

Washing Clothes & Dissolving Sugar

Clarification:

Consider each scenario:

1) For washing clothes, water is essential; without it, washing is ineffective.

2) Connecting brake pedals to brake pads requires solids, not liquids.

3) To deodorize a space, one would likely reach for an aerosol spray, which is a gas.

4) Sculpting involves solid tools and a solid medium.

5) Dissolving sugar necessitates a liquid to be effective!

6) While one might assert that paint is a liquid, it still might not fit the category; I would categorize this application as solid.

7) Gears employed in machinery are solid components!

5 0

12 hours ago

Read 2 more answers

(a) The mass density of a gaseous compound was found to be 1.23 kg m^−3 at 330 K and 20 kPa. What is the molar mass of the compo

castortr0y [923]

Answer:

La masa molar del compuesto es: 168.82 g/mol

La masa molar del gas es: 16.38 g/mol

Explanation:

(a)

Utilizando la ecuación de gases ideales:

$PV=nRT$

donde,

P es la presión

V es el volumen

n es el número de moles

T es la temperatura

R es la constante de los gases, cuyo valor es = 0.0821 L.atm/K.mol

Además,

Moles = masa (m) / Masa molar (M)

La densidad (d) = Masa (m) / Volumen (V)

Así, la ecuación de gases ideales se puede expresar como:

$PM=dRt$

Dado que:-

Presión = 20 kPa = 20000 Pa

La expresión para la conversión de presión en Pascal a presión en atm se muestra a continuación:

P (Pa) = $\frac {1}{101325}$ P (atm)

20000 Pa = $\frac {20000}{101325}$ atm

Presión = 0.1974 atm

Temperatura = 330 K

d = 1.23 kg/m³ = 1.23 g/L

Masa molar =?

Aplica la fórmula:

0.1974 atm × M = 1.23 g/L × 0.0821 L.atm/K.mol × 330 K

⇒M = 168.82 g/mol

La masa molar del compuesto es: 168.82 g/mol

(b)

Dado que:

Presión = 152 Torr

Temperatura = 298 K

Volumen = 250 cm³ = 0.25 L

Utilizando la ecuación de gases ideales:

$PV=nRT$

R = $62.3637\text{torr}mol^{-1}K^{-1}$

Aplicando la fórmula:

152 Torr × 0.25 L = n × 62.3637 L.torr/K.mol × 298 K

⇒n = 0.002045 moles

Dado que:

Masa del gas = 33.5 mg = 0.0335 g

Masa molar =?

La fórmula para calcular los moles se muestra a continuación:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Así,

$0.002045\ moles
= \frac{0.0335\ g}{Molar\ mass}$

La masa molar del gas es: 16.38 g/mol

5 0

1 day ago