The list shows a number of common chemical substances. [5]

Chemistry

1 answer:

SVETLANKA909090 [29]2 years ago

3 0

Answer: Not sure ;c

Explanation:

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Which characteristic is a property of water?

Anettt [7]

D.
The main properties of water are its polarity, cohesion, adhesion, surface tension, high specific heat, and evaporative cooling.

7 0

3 years ago

Balance the following equation: H20 --> H2 + O2

MakcuM [25]

2H2O = 2H2 + O2.

<h3><u>Explanation</u>:</h3>

Balancing equations is very essential because of the fact that it represents the stoichiometric quantities of the reactants needed to react to form the product. The ratio of the weights of reactant and product are also very well understood from this.

Here in this equation, the water is broken into hydrogen and oxygen. The balanced reaction is

2H2O = 2H2 + O2.

Two moles of water is broken down into 2 moles of hydrogen and one mole of oxygen.

5 0

3 years ago

What is the pH of a mixture of 0.042 M NaH2PO4 and 0.058 M Na2HPO4? Hint: The pKa of phosphate is 6.86.

AlekseyPX

Answer:

The pH value of the mixture will be 7.00

Explanation:

Mono and disodium hydrogen phosphate mixture act as a buffer to maintain pH value around 7. Henderson–Hasselbalch equation is used to determine the pH value of a buffer mixture, which is mathematically expressed as,

$pH=pK_{a} + log(\frac{[Base]}{[Acid]})$

According to the given conditions, the equation will become as follow

$pH=pK_{a} + log(\frac{[Na_{2}HPO_{4} ]}{[NaH_{2}PO_{4}]})$

The base and acid are assigned by observing the pKa values of both the compounds; smaller value means more acidic. NaH₂PO₄ has a pKa value of 6.86, while Na₂HPO₄ has a pKa value of 12.32 (not given, but it's a constant). Another more easy way is to the count the acidic hydrogen in the molecular formula; the compound with more acidic hydrogens will be assigned acidic and vice versa.

Placing all the given data we obtain,

$pH=6.86 + log(\frac{0.058}{0.042})$