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kvasek [131]
3 years ago
10

Your teacher gives you a black powder. When you dissolve the powder in water, you see red particles that float to the top, black

particles that sink to the bottom, and a green liquid. Was the black powder a pure substance, mixture, element, or compound? compound element pure substance mixture I think it is A
Chemistry
2 answers:
laila [671]3 years ago
3 0
The answer is B. A mixture can be separated as shown in the example.<span />
IgorC [24]3 years ago
3 0

Answer: Option (a) is the correct answer.

Explanation:

A substance that cannot be broken down into simpler substances is known as an element.

For example, a piece of sodium metal contains only atoms of sodium.

Whereas a compound is defined as a substance that contains two different elements which are chemically combined together in a fixed ratio by mass.

For example, LiCl is a compound in which atoms are present in 1:1 ratio.

A compound is able to dissociate into its constituent particles but an element cannot.

Both an element and a compound are pure substances.

A mixture is defined as a substance in which two or more number of different substances are mixed together. Particles of a mixture never combine chemically to each other.

So, when black powder on coming in contact with water dissociates as red particles that float to the top, black particles that sink to the bottom, and a green liquid. Then it means a chemical reaction has taken place.

Hence, we can conclude that the black powder is a compound.

You might be interested in
2. A sample of gas has a pressure of 195 kPa and a volume of 3.50 L. If the pressure
zhannawk [14.2K]

Answer:

<h2>4.55 L</h2>

Explanation:

The new volume can be found by using the formula for Boyle's law which is

P_1V_1 = P_2V_2

Since we're finding the new volume

V_2 =  \frac{P_1V_1}{P_2}  \\

We have

V_2 =  \frac{195000 \times 3.5}{150000}  =  \frac{682500}{150000}  \\  = 4.55

We have the final answer as

<h3>4.55 L</h3>

Hope this helps you

7 0
3 years ago
Suppose it took 108 joules of energy to raise a bar of gold from 25 °C to 29.7°C. Given that the specific heat capacity of gold
Lady bird [3.3K]

Answer:

m = 180 g

Explanation:

Given data:

Energy absorbed = 108 J

Mas of gold = ?

Initial temperature = 25°C

Final temperature = 29.7 °C

Specific heat capacity of gold = 0.128 J/g.°C

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT =29.7 °C - 25°C

ΔT = 4.7 °C

108 J = m ×0.128 J/g.°C ×4.7 °C

108 J = m ×0.60 J/g

m = 108 J/0.60 J/g

m = 180 g

3 0
3 years ago
atmospheric pressure at elevations of 8000 feet averages about 0.72 atmospheres. Would a cabin pressurized at 500 mm hg meet fed
NeTakaya

Answer:

Yes, but it must be kept at that value and do not let it to decrease more.

Explanation:

Hello.

In this case, in order to substantiate whether the cabin meet the federal standards, we need to convert the 500 mmHg to atm and compare the result with 0.72 atm by knowing that 1 atm equals 760 mmHg:

500mmHg*\frac{1atm}{760mmHg} \\\\=0.66atm

Thus, since 0.66 atm is 0.06 atm away from the federal standard we can infer that it may meet the federal standard, however, it would not be recommended to let the pressure decrease more than that.

8 0
3 years ago
How do you determine the volume of a regular object if you don't know the density?
Ann [662]

Answer:

mol times or devided by molar volume

4 0
3 years ago
The solubility of lead(ii) chloride is 0.45 g/100 ml of solution. what is the ksp of pbcl2? 4.9 × 10-2 1.7 × 10-5 8.5 × 10-6 4.2
Artyom0805 [142]
Answer:
1.7 * 10^-5

Explanation:
1- get the number of moles of PbCl2:
number of moles = mass / molar mass
number of moles = 0.45 / 278.1 = 1.618 * 10^-3 moles

2- get the concentration of Pb2+:
molarity = number of moles of solute / volume of solution in liters
molarity = (1.618 * 10^-3) / (0.1) = 0.0162 M

3- getting concentration of Cl-:
<span>PbCl2(s) <==> Pb2+(aq) + 2Cl-(aq) 
</span>We can note that:
For a certain amount of Pb2+ formed, twice this amount of Cl- is formed.
This means that:
for 0.0162 M of Pb2+, 2*0.0168 = 0.0324 M of Cl- is formed

4- getting Ksp:
Ksp = [Pb2+][Cl-]²
Ksp = (0.0162)*(0.0324)²
Ksp = 1.7 * 10^-5

Hope this helps :)
7 0
3 years ago
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