Answer:
US₂
Explanation:
Uranium sulfide (US₂)
Uranium atomic symbol = U
Sulfur atomic symbol = S
Uranium valency = +4
Sulfur valency = -2
So;
Uranium sulfide (US₂)
Answer:
27%
Explanation:
Hello,
The following information is missing, but I found it: "1.92 g of sodium sulfate is produced from the reaction of 4.9 g of sulfuric acid and 7.8 g of sodium hydroxide" so the undergoing chemical reaction is:

Now, to compute the percent yield, we must first establish the limiting reagent to subsequently determine the theoretical yield of sodium sulfate because the real (1.92g) is already given, thus, we consider the following procedure:

- The moles of sodium hydroxide that completely react with 0.05 moles of sulfuric acid are:

As this number is higher than the previously computed 0.05 moles of available sulfuric acid, one states that the sulfuric acid is the limiting reagent. Now, the theoretical grams of sodium sulfate are found via:

Finally, the percent yield turns out into:

%
Best regards.
Answer:
Many years ago, people living on the Earth, desired to go to the outer space.
Explanation:
When man initiate to go outer space:
Many times ago, people used to think about the world out of Earth, the space and the sky. These thoughts generated the idea of thinking and imagining the space and the moon.
The idea turned into a movie by Georges Méliès, which was inspired by a book written by Jules Verne. The movie gave the idea to Konstantin Tsiolkovsky, a Russian man to develop many ideas which were implemented by Russia and America to build airplanes and rockets that we see launching at present.
A small though became an idea which gave birth to a new invention through which people live their dreams of going in the outer space. Incredible!