Answer:
1. KNO3
2. Ca(NO3)2
3. CaCl2
4. KCl
Explanation:
In each of the neutralization reactions, the H from one of the reactant(acid) will combine with the OH from the other reactant (base) to form water while the other elements combine to give the salt as shown below:
1. HNO3 + KOH → H2O + KNO3
The salt produced is KNO3
2. 2HNO3 + Ca(OH)2 → 2H2O + Ca(NO3)2
The salt produced is Ca(NO3)2
3. 2HCl +Ca(OH)2 → 2H2O + CaCl2
The salt produced is CaCl2
4. HCl +KOH → H2O + KCl
The salt produced is KCl
To determine the pressure in units of kPa, we need to use a conversion factor to convert the units from mmHg to kPa. A conversion factor is a value that would relate two different units and is multiplied or divide to the original measurement depending on what is units is asked. From literature, 1 atm is equal to 760 mmHg and it is also equal to 101.325 kPa. We use these factors to convert the given value. We do as follows:
2150 mmHg ( 1 atm / 760 mmHg ) ( 101.325 kPa / 1 atm ) = 286.643 kPa
Therefore, the closest value from the choices is the second one which has the value of 287, this would be answer.
I believe the answer is C: "<span>It occurs when a hydrogen atom bonds with electropositive atoms."</span>
Answer:
Approximately 75%.
Explanation:
Look up the relative atomic mass of Ca on a modern periodic table:
There are one mole of Ca atoms in each mole of CaCO₃ formula unit.
- The mass of one mole of CaCO₃ is the same as the molar mass of this compound:
. - The mass of one mole of Ca atoms is (numerically) the same as the relative atomic mass of this element:
.
Calculate the mass ratio of Ca in a pure sample of CaCO₃:
.
Let the mass of the sample be 100 g. This sample of CaCO₃ contains 30% Ca by mass. In that 100 grams of this sample, there would be
of Ca atoms. Assuming that the impurity does not contain any Ca. In other words, all these Ca atoms belong to CaCO₃. Apply the ratio
:
.
In other words, by these assumptions, 100 grams of this sample would contain 75 grams of CaCO₃. The percentage mass of CaCO₃ in this sample would thus be equal to:
.