Answer:
Explanation:
The molarity of the solution can be found by using the formula:
c is the concentration in M , mol/dm³ or mol/L
v is the volume in L or dm³
m is the mass in grams
M is the molar mass in g/mol
From the question;
mass = 5 g
Molar mass (M) of KCl = 39 + 36.5 = 75.5 g/mol
Since the volume is in mL it has to be converted to litres.
v = 0.1 L
We have the final answer as;
(2) O2 (4) NH3
Answer:
They are composed by two or more pure substances.
Explanation:
Hello,
At first, we must take into account that mixtures are such materials made up of two or mire pure substances, say elements, molecules or compounds. They are classified as homogeneous for which there is no appreciable difference upon its constituents and as heterogeneous for which the constituents are differentiable. Now, stainless steel is considered as a mixture as long as it is mainly composed by iron and carbon and some other metallic elements such as chromium. Sea water is another interesting example, since the main constituents are water and sodium chloride, nonetheless, other ions such as iodide, sulfate, magnesium (II), potassium (I), calcium (II) are also found into it. Finally, the air is a mixture due to the presence of oxygen and nitrogen as the major constituents, considering others such as carbon dioxide, methane (pollution), argon, hydrogen as traces, it means, compositions below the 1%.
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Answer:
The answer to your question is below
Explanation:
An endothermic reaction absorbs heat to proceed.
An exothermic reaction releases heat to proceed.
A. When a certain amount of potassium nitrate is dissolved in water, the water temperature drops from 23°C to 18°C. This is an example of an endothermic reaction because of the temperature diminishes.
B. Jack cooks himself a steak. This is an endothermic reaction because the steak does not cook itself it needs heat to be cooked.
C. When cold water is mixed with sulphuric acid, the mixture can rapidly reach the boiling point of water. This is an exothermic reaction because the temperature of water increases, which means that energy is been released.
D. A flare burns up slowly. I think it is an endothermic reaction because it was supply energy to proceed.
(1) argon (3) chlorine
(2) bromine (4) sulfur
Answer: Option (2) is the correct answer.
Explanation:
STP means standard temperature and pressure.
At STP chlorine exists as a gas, sulfur exists as a solid and argon also exists as a gas.
Whereas bromine exists as a liquid at STP.
Thus, we can conclude that out of the given options bromine is the element which exists as a liquid at STP.
The element that is a liquid at standard temperature and pressure (STP) is bromine (Br). Therefore, option 2 is correct.
Bromine is the only element among the options given that is a liquid at STP. It is a reddish-brown liquid with a strong and unpleasant odor. Bromine is a halogen and exists as diatomic molecules (Br₂).
It has a boiling point of 58.8°C (137.8°F) and a melting point of -7.2°C (19.0°F). Bromine is significantly more reactive than argon but less reactive than chlorine and sulfur.
Argon (Ar) is a noble gas and exists as a colorless and odorless gas at STP. Chlorine (Cl) is a greenish-yellow gas at STP. Sulfur (S) is a solid at STP and melts at a relatively high temperature.
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