<span>1.91 mol H2
Let's rewrite that equation into a balanced equation. Let's start with the unbalanced version:
Na + HF ==> NaF + H2
We have equal amounts of Na and F on both sides, but twice as much H on the right. So let's double the Na, HF, and NaF coefficients.
2Na + 2HF ==> 2NaF + H2
And we now have equal quantities of all elements on both sides, so our equation is balanced.
Now looking at the balanced equation, 2 moles of sodium should produce 1 mole of hydrogen gas. So we should have 4.50/2 = 2.25 moles of hydrogen gas. But we only have an 85% yield, so we multiply the expected yield by the percentage, giving 2.25 mol * 0.85 = 1.9125 mol. Rounding to 3 significant figures gives us 1.91 mol which matches "1.91 mol H2"</span>
Transparent - when light is in context with transparent materials almost all of the the light is allowed to go through these materials.
Ex: glass
Translucent- materials that do not allow light to pass through easily.
Ex: tissue paper
Opaque- materials that allow no light to go through them .
Ex: wood
The answer is D - zinc sulphate and hydrogen
Answer:
Limestone is easily eroded from above and below.
Explanation:
The Florida bedrock is largely made of limestone. Because limestone is a rock that is easily eroded, the landscape of a great part of Florida is classified as karstic.
Karstic landscapes are dotted by sinkholes, underground rivers, caves, and springs. The more acidic the groundwater or rainwater, the faster and more easily the limestone will succumb to erosion.
In this way, underground rivers, streams, runoff, rain, and underground water pooled in caves have all carved out gaps and caverns in the weak limestone bedrock.
Answer:
Explanation:
Hello there!
In this case, it possible to use the Rydberg equation in order to calculate the wavelength for this transition from n=3 to n=2 as shown below:
Thus, we plug in the corresponding energy levels and the Rydberg constant to obtain:
Best regards!
