Answer:
554.86kj
Explanation: Since 1 mole of CaC2=15.14kj yield 1mole of C2H2
The enthalpy change of H2O is 2*285=570
570+-15.14=554.86kj
Hence Hp is 554.86kj
He=Hp
40.0 g ( 1 mole ) --------------- 6.02x10²³ molecules
? ? --------------------------- 2.90x10²² molecules
mass = 2.90x10²² * 40.0 / 6.02x10²³
mass = 1.16x10²⁴ / 6.02x10²³
mass = 1.9269 g
hope this helps!
B! because the hydrogen causes some nuclear reactions.
Answer:
Here's it:
Explanation:
Germs are everywhere! They can get onto hands and items we touch during daily activities and make us sick. Cleaning hands at key times with soap and water or hand sanitizer that contains at least 60% alcohol is one of the most important steps you can take to avoid getting sick and spreading germs to those around you.
There are important differences between washing hands with soap and water and using hand sanitizer. Soap and water work to remove all types of germs from hands, while sanitizer acts by killing certain germs on the skin. Although alcohol-based hand sanitizers can quickly reduce the number of germs in many situations, they should be used in the right situations.
Answer:
Explanation:
The two requirements for a measurement are a <u>number</u> and a <u>unit.</u>
For example, here is a measurement:
38.6 cm
The <u>number</u> is 38.6 and the <u>unit</u> is cm, or centimeters.
Therefore, both <em>number </em>and <em>unit</em> are correct.
