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2 years ago

2. Identify the following as human (H) or nonhuman (N) possible sources of error:

Chemistry

1 answer:

guajiro [1.7K]2 years ago

5 0

Answer:

a. H

b. H

c. N

d. N

Explanation:

a. Human error - It should be their responsibility to calibrate the balance

b. Human error - they should've known to put the right amount of sig figs.

c. Nonhuman error - they can't control the temperature

d. Nonhuman error - the balance must've been broken, therefore not a human error

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If 50.0 g of water saturated with potassium chloride at 80.0°C is slowly evaporator to dryness, how many grams of the dry salt w

balu736 [363]

Answer:

25.0 g.

Explanation:

From the solubility curve that is shown in the attached image, the solubility of KCl per 100.0 g of water is about 50.0 g.

So, a saturated solution of KCl in 50.0 g of water will contain about 25.0 g.

Thus, the grams of the dry salt that will be recovered is 25.0 g.

5 0

3 years ago

Drinking water may contain a low concentration of lead ion (Pb2 ) due to corrosion of old lead pipes. The EPA has determined tha

Lynna [10]

Answer:

3.861x10⁻⁹ mol Pb⁺²

Explanation:

We can define ppm as mg of Pb²⁺ per liter of water.

We calculate the mass of lead ion in 100 mL of water:

100.0 mL ⇒ 100.0 / 1000 = 0.100 L

0.100 L * 0.0080 ppm = 8x10⁻⁴ mg Pb⁺²

Now we convert mass of lead to moles, using its molar mass:

8x10⁻⁴ mg ⇒ 8x10⁻⁴ / 1000 = 8x10⁻⁷ g

8x10⁻⁷ g Pb²⁺ ÷ 207.2 g/mol = 3.861x10⁻⁹ mol Pb⁺²

4 0

3 years ago

55 L of a gas at 25oC has its temperature increased to 35oC. What is its new volume?

ladessa [460]

Answer:

Approximately 56.8 liters.

Assumption: this gas is an ideal gas, and this change in temperature is an isobaric process.

Explanation:

Assume that the gas here acts like an ideal gas. Assume that this process is isobaric (in other words, pressure on the gas stays the same.) By Charles's Law, the volume of an ideal gas is proportional to its absolute temperature when its pressure is constant. In other words

$\displaystyle V_2 = V_1\cdot \frac{T_2}{T_1}$ ,

where

$V_2$ is the final volume,
$V_1$ is the initial volume,
$T_2$ is the final temperature in degrees Kelvins.
$T_1$ is the initial temperature in degrees Kelvins.

Convert the temperatures to degrees Kelvins:

$T_1 = \rm 25^{\circ}C = (25 + 273.15)\; K = 298.15\; K$ .

$T_2 = \rm 35^{\circ}C = (35 + 273.15)\; K = 308.15\; K$ .

Apply Charles's Law to find the new volume of this gas:

$\displaystyle V_2 = V_1\cdot \frac{T_2}{T_1} = \rm 55\;L \times \frac{308.15\; K}{298.15\; K} = 56.8\; L$ .

8 0

3 years ago

Diffusion is a general term referring to the net movement of atoms and molecules along a concentration gradient, from an area of

aniked [119]

Answer:

Higher concentration to an area of lower concentration

Explanation:

When you open a perfume bottle at a corner of a room, after a while, its fragrance can be perceived across a distance at the other end of the room. This is because, molecules of the compound in the fragrance have moved from the area of higher concentration in the perfume bottle, across a concentration gradient to a region of lower concentration at the other end of the room. This is diffusion.

7 0

2 years ago

A certain metal M forms a soluble sulfate salt MSO, Suppose the left half cell of a galvanic cell apparatus is filled with a 3.0

bija089 [108]

Answer:

E = 0.062 V

Explanation:

(a) See the attached file for the answer

(b)

Calculating the voltage (E) using the formula;

E = - (2.303RT/nf)log Cathode/Anode

Where,

R = 8.314 J/K/mol

T = 35°C = 308 K

F- Faraday's constant = 96500 C/mol,

n = number of moles of electron = 2

Substituting, we have

E = -(2.303 * 8.314 *308/2*96500) *log (0.03/3)

= -0.031 * -2

= 0.062V

Therefore, the voltmeter will show a voltage of 0.062 V

5 0

2 years ago