Yes, you should memorize them. While it is easy to predict them by looking at a periodic table, you should still have a strong grasp of simpler chemistry such as this before more challenging topics are taught.
Answer:
9.8g
Explanation:
Using periodic table find molar mass of C and H:
C=12.01g/mol
H=1.008g/mol
Molar mass of C2H4=(12.01)2+(1.008)4=28.03g/mol
Using molar mass times moles of the chemical to find the mass in 0.35 moles of c2h4:
28.03 x 0.35=9.8grams
Answer:
To convert a decimal into scientific notation, move the decimal point until you get to the left of the first non-zero integer. The number of places the decimal point moves is the power of the exponent, because each movement represents a "power of 10".
The most widely accepted explanation of how the solar system formed is called the nebular hypothesis. According to this hypothesis, the Sun and the planets of our solar system formed about 4.6 billion years ago from the collapse of a giant cloud of gas and dust, called a nebula
I hope this helps
