10. Can you write an equation to describe this? (Investigating the pH scale)

Calculate the empirical formula for each stimulant based on its elemental mass percent composition.

Vanyuwa [196]

A.
elements    C    H    N
percentage composition    74.03    8.70 17.27
Molecular mass 12    1    14

# of mole    6.17    8.70    1.23

÷smallest mole    5.0 7.0 1.0

mole ratio    5    : 7    ; 1

THE EMPERICAL FORMUKLA FOR A. IS C5H7O

NOTE: #of mole = percentage composition ÷ Mr
and the ÷ smallest mole is used to find the ratio...for the above question a. it is 1.23

and b. should be done using the same procedure

3 0

3 years ago

Read 2 more answers

Sam wished to investigate how fertilizer run-off affects the growth of algae in freshwater lakes and streams. He set his experim

MrMuchimi

Answer:

amount of fertaliser--> the independant variable is the one being changed

8 0

3 years ago

How many grams of O2 are needed to react with 8.15 g of C2H2?

xxTIMURxx [149]

Answer:

25.08 grams of O₂ are needed to react with 8.15 g of C₂H₂.

Explanation:

The balanced reaction is:

2 C₂H₂ + 5 O₂ → 4 CO₂ + 2 H₂O

By reaction stoichiometry, the following amounts of moles of each compound participate in the reaction:

C₂H₂: 2 moles
O₂: 5 moles
CO₂: 4 moles
H₂O: 2 moles

The molar mass of each compound is:

C₂H₂: 26 g/mole
O₂: 32 g/mole
CO₂: 44 g/mole
H₂O: 18 g/mole

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

C₂H₂: 2 moles* 26 g/mole= 52 g
O₂: 5 moles* 32 g/mole= 160 g
CO₂: 4 moles* 44 g/mole= 176 g
H₂O: 2 moles* 18 g/mole= 36 g

Then you can apply the following rule of three: if by stoichiometry 52 grams of C₂H₂ react with 160 grams of O₂, 8.15 grams of C₂H₂ react with how much mass of O₂?

$mass of O_{2} =\frac{8.15 grams of C_{2} H_{2}*160 grams of O_{2} }{52 grams of C_{2} H_{2}}$

mass of O₂= 25.08 grams

25.08 grams of O₂ are needed to react with 8.15 g of C₂H₂.

8 0

3 years ago

Indicate which solution in each pair has the lower pH. Your response should be a four letter "word". The first letter should be

JulijaS [17]

Answer:

bcfh

Explanation:

HClO₄ reacts with water thus:

HClO₄ + H₂O → H₃O⁺ + ClO₄⁻

That means HClO₄ produce H₃O⁺ that decreases pH. That means the higher concentration of HClO₄ decreases pH. Thus, lower pH will be:

b) 0.2 M HClO4

The reaction of NaClO₄ is:

NaClO₄ + H₂O → OH⁻ + HClO₄ + Na⁺

The higher concentration of NaClO₄ the higher production of OH⁻ that increase pH, that means the lower concentration of NaClO₄ the lower pH, thus, the answer is:

c) 0.1 M NaClO or

HF reacts with water thus;

HF ⇄ H⁺ + F⁻

The equilibrium constant is:

k = [H⁺] [F⁻] / [HF] = 3,5x10⁻⁴

For HNO₂ equilibrium is:

HNO₂ ⇄ H⁺ + NO₂⁻

k = [H⁺] [NO₂⁻] / [HNO₂] = 4,5x10⁻⁴

As k value is higher for HNO₂, the concentration of H⁺ will be higher in this system doing the HNO₂ with the lower pH.

f) 0.1 M HNO2

NaOH is a strong base that produce OH⁻ that increase pH, pure water is neutral, thus, the lowe pH is:

h) pure water

I hope it helps!

7 0

4 years ago

I

Bond [772]

Answer:

about 0.7 g/mL

Explanation:

Density = mass ÷ volume

D = 5.29 g / (12.6 mL - 5.00 mL)

D = 5.29 g / 7.6 mL

D = 0.696052.... g/mL

D = about 0.7 g/mL

5 0

4 years ago