Answer:
C
Explanation:
A physical change is one in which no new substance is formed. The moistening of food by saliva is purely a physical change because no new substance is formed in the process.
A chemical change leads to the formation of a new substance. The action of the enzyme converts starch into sugar which means that a new substance is formed. This is a chemical change.
Im a bit torn here, lets look at the definitions of physical and chemical changes:
physical change changes only the phase/state of a substance, but not what the substance is
chemical change is a chemical reaction where a new substance is formed and energy is given off or absorbed.
(it just started raining and it smells really nice out my window)
clearly, this cannot be just a physical reaction. i think i would be inclined to pick B. but C. could have merit as an answer too. sorry for the ambiguity x
Answer:
Length = 393pm, Density = 21.3 g/cm^3.
Explanation:
From the question above, we have the following parameters or data which is going to aid in solving the above Question.
=> The radius of a platinum atom = 139 pm.
Therefore, the length can be calculated by making use of the formula given below:
Length = 2 √( 2r) = 2 × √ (2 × 139 × 10^-12m ) = 393 × 10^-10 m = 393pm.
The density can be calculated by making use of the chemical formula given below:
Density = mass ÷ volume = (195.064/ 6.02 × 10^23) ÷ (3.93 × 10^-10/ 10^-2) = 21.3 g/cm^3.
Answer:
Molarity = 0.4M
Explanation:
Molar mass of NaOH (M)= 40
m= 8g, V= 500ml=0.5L
n= m/M=[8/40]= 0.2mol
Applying
n= CV
0.2= C×0.5
C= 0.4M
