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NISA [10]
3 years ago
14

Please help! I need answers please!

Chemistry
1 answer:
eduard3 years ago
3 0
2. <span>B: aluminum
</span>
3. <span>D: Scientists could not agree on a standard.

4.</span>B: Nonmetals
You might be interested in
Is KNO a strong acid?
stira [4]

Answer:

First of all, it's KNO₃ not KNO.

Second, KNO₃ is neither an acid nor it is a base, infact, it is a salt and therefore it's neutral.

hope that helps...

3 0
2 years ago
Which salt is produced when sulfuric acid and calcium hydroxide react completely?
AnnyKZ [126]

Answer: Option (4) is the correct answer.

Explanation:

When sulfuric acid reacts with calcium hydroxide then it results in the formation of calcium sulfate and water.

The chemical reaction for the same will be as follows.

     H_{2}SO_{4} + Ca(OH)_{2} \rightarrow CaSO_{4} + 2H_{2}O

Thus, we can conclude that CaSO_{4} salt is produced when sulfuric acid and calcium hydroxide react completely.

3 0
3 years ago
Read 2 more answers
Mercury (Hg) poisoning is a debilitating disease that is often fatal. In the human body, mercury reacts with essential enzymes l
alisha [4.7K]

Answer:

6 x 10⁵ kg Hg

Explanation:

The mass of mercury in the entire lake is found by multiplying the concentration of the mercury by the volume of the lake.

The volume of the lake is calculated in cubic feet:

V = (SA)x(depth) = (100mi²)(5280ft/mi)² x (20ft) = 5.57568 x 10¹⁰ ft³

Cubic feet are then converted to mL (1cm³=1mL)

(5.57568 x 10¹⁰ ft³) x (12in/ft)³ x (2.54cm/in)³ = 1.578856752 x 10¹⁵ mL

The mass of mercury is then found:

m = CV = (0.4μg/mL)(1g/10⁶μg)(1kg/1000g) x (1.578856752 x 10¹⁵ mL) = 6 x 10⁵ kg Hg

3 0
3 years ago
Select True or False from the pull down menus for the following statements.
Shkiper50 [21]

Answer:

First question: 1- False, 2- True, 3- False, 4 -Tue, 5- True.

Second question: 12.7 ºC

Explanation:

First question:

1- When a phase change for a pure substance is taking place under constant pressure, the temperature remains constant, and there's no sensitive heat flowing, but there's latent heat flow, which must be added to separate the molecules and to increase the kinetic energy.

2- When observed the heating and the cooling curve, at the phase change, there is no change in temperature, so it must be a horizontal line, which has a slope equal to 0.

3- Heat is the energy that is transferred by the substances or bodies because of a difference in temperature. The temperature is the measure of average kinetic energy in the molecules, so they are different.

4- As explained above, it's true, that's the definition of temperature.

5- Melting and freezing are the opposite processes and they occur at the same temperature. The difference is that for melting, the substance is absorbing heat, and for freezing it is losing heat, but the heat amount is the same for both process and is calculated by Q = ±m*L, where Q is the heat, m the mass, L the heat capacity, and the signal ± indicates if the substance is absorbing (+) or losing (-) heat.

Second question:

For the conservation of energy, the total amount of heat must be 0. The coin is losing heat, so it must be negative. The water is gaining heat, so it must be positive:

Qw - Qc = 0

Q = m*s*ΔT, where Q is the heat, m is the mass, s is the specif heat, and ΔT the temperature variation (final - initial). Qw is from water and Qc for the coin. The specif heat from the water is 4.184 J/gºC. At the thermal equilibrium, the final temperature must be equal for both.

mw*sw*ΔTw = mc*sc*ΔTc, if the coin is pure silver, sc = 0.233 J/gºC

27.0*4.184*(T - 15.5) = 15.5*0.233*(T - 100)

112.968*(T - 15.5) = 3.6115*(T - 100)

112.968T - 1751.004 = 3.6115T - 361.15

109.3565T = 1389.854

T = 1389.854/109.3565

T = 12.7ºC

So, the final water temperature would be 12.7ºC, which is impossible because it needs to increase. So the coin is not silver pure.

7 0
3 years ago
The statement “the scientific process is open ended” means:
mina [271]

Answer:

think it helps you

<h2>Explanation:</h2>

<em><u>The statement “the scientific process is open ended” means: Would an element with 7 valence electrons be more or less reactive than an element with 3 valence electrons? Element 1 is a hard dark-red solid</u></em>

4 0
3 years ago
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