All categories

3 years ago

What is the law of conservation on mass?

2 answers:

6 0

<span>Mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. The mass of the products in a chemical reaction must equal the mass of the reactants.</span>

OLga [1]3 years ago

4 0

Matter cannot be created nor destroyed but regrouped (recycled)

You might be interested in

Please answer quickly

Stolb23 [73]

Inherited it from his grandfather

8 0

3 years ago

Which symbol represents a particle with a total of 10 electrons

vova2212 [387]

Al3+ is the answer. :)

7 0

3 years ago

In a hot shower or steam room, you look up at the ceiling. What do you observe on the ceiling and why?

Evgen [1.6K]

Steam rises to the top and stays there

3 0

4 years ago

A 200.0 mL solution of 0.40 M ammonium chloride was titrated with 0.80 M sodium hydroxide. What was the pH of the solution after

choli [55]

Answer:

9.25

Explanation:

Let first find the moles of $NH_4Cl$ and $NaOH$

number of moles of $NH_4Cl$ = 0.40 mol/L × 200 × 10⁻³L

= 0.08 mole

number of moles of $NaOH$ = 0.80 mol/L × 50 × 10⁻³L

= 0.04 mole

The equation for the reaction is expressed as:

$NH^+_{4(aq)} \ + OH^-_{(aq)} ------> NH_{3(g)} \ + H_2O_{(l)}$

The ICE Table is shown below as follows:

$NH^+_{4(aq)} \ + OH^-_{(aq)} ------> NH_{3(g)} \ + H_2O_{(l)}$

Initial (M) 0.08 0.04 0

Change (M) - 0.04 -0.04 + 0.04

Equilibrium (M) 0.04 0 0.04

$K_a*K_b = 10^{-14} \ at \ 25^0C$

$K_a = \frac{10^{-14}}{K_b}$

$K_a = \frac{10^{-14}}{1.76*10^{-5}}$

$K_a= 5.68*10^{10}$

$pK_a = - log \ (K_a)$

$pK_a = - log \ (5.68*10^{-10})$

$pK_a = 9.25$

$pH = pKa + \ log (\frac{HB}{HA} )$ for buffer solutions

$pH = pKa + \ log (\frac{moles \ of \ base }{ moles\ of \ acid} )$ since they are in the same solution

$pH = 9.25 + \ log (\frac{0.04 }{ 0.04} )$

$pH = 9.25$

8 0

3 years ago

What is the hydrogen ion concentration of a solution with a pH 5? *

nekit [7.7K]

Answer:

In the same way, a solution with a pH of 5 contains 10-5mol/l of hydrogen ions, a solution with a pH of 6 contains 10-6mol/l of hydrogen ions, while the solution with a pH of 7 contains 10-7mol/l of hydrogen ions.

Explanation:

5 0

4 years ago