Answer:
Explanation:
a) In an exothermic reaction, the energy transferred to the surroundings from forming new bonds is ___more____ than the energy needed to break existing bonds.
b) In an endothermic reaction, the energy transferred to the surroundings from forming new bonds is ___less____ than the energy needed to break existing bonds.
c) The energy change of an exothermic reaction has a _____negative_______ sign.
d) The energy change of an endothermic reaction has a ____positive________ sign.
The energy changes occur during the bonds formation and bonds breaking.
There are two types of reaction endothermic and exothermic reaction.
Endothermic reactions:
The type of reactions in which energy is absorbed are called endothermic reactions.
In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.
For example:
C + H₂O → CO + H₂
ΔH = +131 kj/mol
it can be written as,
C + H₂O + 131 kj/mol → CO + H₂
Exothermic reaction:
The type of reactions in which energy is released are called exothermic reactions.
In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.
For example:
Chemical equation:
C + O₂ → CO₂
ΔH = -393 Kj/mol
it can be written as,
C + O₂ → CO₂ + 393 Kj/mol
Elements and compounds are both examples of pure substances. Compounds are substances that are made up of more than one type of atom. Elements are the simplest substances made up of only one type of atom. i hope that helps:)
Answer:
142240
Explanation:
We are told in the question:
Height of Gateway Arch in St. Louis, MO = 630ft
We are asked, how many U.S. dimes would be in a stack of the same
height when 1 dime is 1.35 mm thick.
Step 1
Convert height in ft to mm
1 ft = 304.8 mm
630ft =
Cross Multiply
630ft × 304.8mm/1ft
= 192024 mm.
Step 2
To find how many US dimes would be in a stack of the same height
= Total thickness/ Thickness of 1 US dime
= 192024 mm/1.35mm
= 142240
Therefore, the number of dimes that would be in a stack of the same
height is 142240
D is the answer. A, B,C are absurd. Doing a little word right there.
Answer:
1.67g/cm3
Explanation:
The formula for density is . The m variable stands for mass and the v variable stands for volume.
The mass of the brown sugar is 10.0g and the volume is 6.0cm3, so we can plug those values into the equation.
Rounded to 3 significant figures, the density of the block of brown sugar is 1.67 g/cm3. If the mass is in grams and the volume is in cm3, the unit for the final answer is (grams per centimetres cubed).