Answer:
We need add acid to prepare 0.15 acetate buffer with pH 3.7.
Explanation:
As we know that buffer solution is the combination of weak acid with strong base or strong acid with weak base.
We know that CH3COOH is weak acid .Acetate buffer is the combination of weak acid CH3COOH and conjucate base CH3COO- (from salt).
So we have to add acid to achieve the proper final pH value of mixture.We need add acid to prepare 0.15 acetate buffer with pH 3.7.
Answer is: A. pure substance.
Pure substance is made of only one type of atom (chemical element) or only one type of molecule (chemical compound), it has definite and constant composition with distinct chemical properties.
Glucose is chemical compound composed of carbon, hydrogen and oxygen atoms connected with covalent bonds.
Pure substances can be separated chemically, not physically, that is difference between pure substances and mixtures.
Answer:
H2 and O2
Explanation:
A coffee cup calorimeter is basically a type of calorimeter that operates at constant pressure. The heat measured in the calorimeter is equal to the change in enthalpy of the reaction.
This type of calorimeter is apt for reactions involving solutions where there is little or no change in volume.
It is not generally applicable to gas phase reactions such as the reaction between H2 and O2.
Answer:
This is the tendency for particles in suspension to settle out of fluid in which they are contained and come to rest against a barrier.
Explanation:
In sedimentation, the particles are in a fluid and under the influence of forces , for example, gravitational forces, they settle and then come to rest when faced with a barrier.
The settling process is the process in which the particles fall out of liquid and sedimentation is the end of the process.
Answer:
0.467 kilograms of protein or carbohydrates
Explanation:
First, there is a need to understand that <em>1 kJ = 0.239 kCal</em>
Hence, 17 kJ = 17 x 0.239 = 4.063 kCal
The race requires 650.0 kCal/hr and has to last for 175 minutes.
175 minutes = 175/60 = 2.917 hrs
The total kCal requires for the race = 650 x 2.917 = 1,895.833 kCal
1 g of protein or carbohydrate food produces 17.0 kJ or 4.063 kCal of energy. Hence, the total g of protein or carbohydrate that will produce 1,895.833 kCal of energy would be;
1,895.833/4.063 = 466.609 g
<em>1 g = 0.001 kg</em>
466.609 g = 466.609 x 0.001 = 0.467 kg
<em>Hence, </em><em>0.467 </em><em>kilograms of proteins or carbohydrates must be consumed.</em>