All categories

3 years ago

A substance undergoes a change. Which of the following indicates that the change

Chemistry

1 answer:

LekaFEV [45]3 years ago

5 0

Answer:

change of color

Explanation:

when a substance undergoes a change of color it is an indication that it was chemical

You might be interested in

Which element is present in all organic compounds?

Mkey [24]

The anser is 1, carbon

5 0

3 years ago

Read 2 more answers

What is the percent composition by mass of hydrogen in nh4hco3

Simora [160]

Answer: The percent composition by mass of hydrogen in given compound is 6.33 %

Explanation:

We are given:

A chemical compound having chemical formula of $NH_4HCO_3$

It is made up by the combination of 1 nitrogen atom, 5 hydrogen atoms, 1 carbon atom and 3 oxygen atoms

To calculate the percentage composition by mass of hydrogen in the compound, we use the equation:

$\%\text{ composition of Hydrogen}=\frac{\text{Mass of hydrogen}}{\text{Mass of compound}}\times 100$

Mass of compound = $[(1\times 14)+(5\times 1)+(1\times 12)+(3\times 16)]=79g/mol$

Mass of hydrogen = $(5\times 1)=5g/mol$

Putting values in above equation, we get:

$\%\text{ composition of Hydrogen}=\frac{5g/mol}{79g/mol}\times 100=6.33\%$

Hence, the percent composition by mass of hydrogen in given compound is 6.33 %

6 0

3 years ago

Is the center of an atom is called the nucleus?

Nuetrik [128]

Answer:

The center of the atom contains the nucleus so yes

Explanation:

3 0

3 years ago

A 1.00 liter solution contains 0.43 M hydrofluoric acid and 0.56 M potassium fluoride. If 0.280 moles of potassium hydroxide are

kolbaska11 [484]

Answer:

Answers are in the explanation

Explanation:

Equlibrium of HF in H₂O is:

HF + H₂O ⇄ F⁻ + H₃O⁺

Now, the KOH reacts with HF, thus:

KOH + HF → F⁻ + H₂O

That means after reaction, concentration of HF decrease increasing F⁻ concentration.

Now, seeing the equilibrium, as moles of HF decrease and F⁻ moles increase, the equilibrium will shift to the left decreasing H₃O⁺ concentration.

For the statements:

A. The number of moles of HF will increase. FALSE. HF react with KOH, thus, moles of HF decrease

B. The number of moles of F- will decrease. FALSE. The reaction produce F⁻ increasing its moles.

C. The equilibrium concentration of H₃O⁺ will increase. FALSE. The equilibrium shift to the left decreasing concentration of H₃O⁺

D. The pH will decrease. FALSE. As the H₃O⁺ concentration decrease, pH will increase

E. The ratio of [HF] / [F-] will remain the same. FALSE. Because moles of HF are decreasing whereas F- moles are increasing changing, thus, ratio.

6 0

3 years ago

Blank can be made in the field or in the laboratory

Masteriza [31]

It would most likely be a observation or hypothesis

5 0

3 years ago