The Patch's area of the space shuttle in km² is 2.07 × 10⁻⁹ km²
Given, that a space shuttle requires a 20.7 cm² patch
We have to convert the patch's area from cm² into km².
Unit conversion is a method in which we multiply or divide with a particular numerical factor and then finally round off to the nearest significant digits.
Patch area of the space shuttle is 20.7 cm²
1 cm = 0.00001 km
or, 1 cm² = (0.00001 km)²
or, 1 cm² = 10⁻¹⁰km²
20.7 cm² = 20.7 × 10⁻¹⁰km²
20.7 cm² = 2.07 × 10⁻⁹ km²
The patch area in square kilometers is 2.07 × 10⁻⁹ km²
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the answer is C) . I hope this was helpful!
Answer:


Explanation:
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In this case, since the reaction (A->B) have an initial amount of pure 4-aminobenzoic acid, the first step to compute the theoretical yield is to solve the following stoichiometric setup:

Whereas A stands for 4-aminobenzoic acid and B for the benzocaine. Moreover, we compute the percent yield by dividing the actual yield (0.318 g) by the theoretical one (0.365 g):

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Answer:
D
Explanation:
In a Helium (He) atom, the atomic structure of the atom has 2 protons, 2 electrons and 2 neutrons. For an element X to be a Helium (He) atom, it must possess 2 protons. The number of neutrons present will determine its stability either if its probably radioactive or a natural occurring inert gas.
In option 1,
We have H-2. The symbol "H" is used to denote the element hydrogen in the periodic table and hydrogen has only 1 protons and 1 neutron making its mass number 2.
Option 2,
He -2 : here in this option, we have a helium atom, but with mass number of 2 only. Judging from the formula of mass number = protons + neutrons, we already have proton as 2, hence the number of neutrons there is zero (0)
Option 3,
He - 3 : just like in option 2, the only difference here is that the mass number is 3 hence making the number of neutrons just 1.
Option 4,
He - 4 : This option met the requirements of having 2 protons and 2 neutrons making a total of 4 which corresponds to the mass number.