A.
Physical change
Step by step explanation;:)
Given :
Human blood should have around 1.04 kg/L platelets.
A blood sample of 4.01 milliliters is collected from a patient to be analyzed for a platelet count.
To Find :
The expected mass in grams of platelets in the blood sample.
Solution :
1 L of human blood contains 1.04 kg of platelets.
So, amount of platelets is 1 ml blood is :

Mass of platelets in 4.01 ml blood is :

Hence, this is the required solution.
To determine the amount of a certain element in a compound, we use the ratio of the elements from the compound. We calculate is follows:
45.0 g CCl4 ( 1 mol CCl4 / 153.82 g CCl4 ) ( 1 mol C / 1 mol CCl4 ) ( 12.01 g C / 1 mol C ) = 3.5135 g carbon present
Hope this answers the question. Have a nice day.
Answer:
The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.
Explanation:
..[1]
..[2]
..[3]
..[4]
Using Hess's law:
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
2 × [4] = [2]- (3 ) × [1] - (2) × [3]




The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.