The enthalpy change for an exothermic reaction is negative because heat is being released, so that takes out two of the responses. Since energy is being released into the surroundings due to the exothermic reaction, the potential energy of the products is lower than that of the reactants. Energy is being put in to make the reaction occur, but then that energy is all being released into the surroundings thus a lower potential energy level for the products
Scientists can measure the height in
different units but problem could arise when they compare all the measurements.
That is the reason there is standard units for measurements.
<span>There may be error arises when an
American scientist is measuring the height of an object in inches and other Australian
scientist is measuring the height of same object in meters. Their data cannot
be compared because they are using different units to measure height.</span>
Answer:- C. Hafnium.
Solution:- Mass of the sample is 46.0 g and it's volume is 
.
From mass and volume, we can calculate it's density using the formula:
On the basis of the density, this substance could either be mercury or hafnium. Since the substance is a solid at room temperature where as mercury is liquid. So, it can't be mercury.
The right choice is C) Hafnium.
Answer:
D.
Explanation:
Carbon atoms are not strongly electronegative and tend to form covalent bonds.
Molar concentration is a measure of the concentration of a solute in a solution, or of any chemical species, in terms of amount of substance per unit volume.
