1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
e-lub [12.9K]
3 years ago
9

Please can u help me .

Chemistry
2 answers:
Marysya12 [62]3 years ago
7 0

Answer:

4 is D 5 is A

Explanation:

sdas [7]3 years ago
4 0

QUESTIONS !

  • 1. Why might pesticides sprayed onto the fields reduce a bean crop?

A Pesticides damage plant leaves.

B Pesticides damage plant roots.

C Pesticides kill insects that feed on bean plants.

D Pesticides kill insects that pollinate bean plants.

  • 2. What may cause the rapid growth of plants in a lake?

A excess fertilizers

B excess herbicides

C low water pH

D low water temperature

ANSWER !

  • 1. (D) Pesticides kill insects that pollinate bean plants.
  • 2. (B) Excess Herbicides

EXPLANATION !

  • 1. When a field is sprayed with a pesticide, not all of the insects will die, and the ones that remain will produce offspring that will also be tolerant to the spray. This forces farmers to use more and different kinds of pesticides, so they can kill all of the insects that might destroy their crop.
  • 2. During periods of heavy rainfall, increased runoff brings more nutrients into a lake. These additional nutrients may be released from flooded soils or carried into the lake on silt or clay particles. Excess nutrients often boost plant growth, particularly algae or free-floating aquatic plants.                       <em>PLEASE MARK AS BRAINLIEST !!!!</em>
You might be interested in
Which factors affect electronegativity?
nasty-shy [4]
I believe d is the correct answer
3 0
3 years ago
Read 2 more answers
Use Hess law and the following equations to calculate H for the reactio below
aleksandr82 [10.1K]

Answer: B2H6 (g) + 3O2 (g) → B2O3 (s) + 3H2O (g) (ΔH = -2035 kJ/mol) 3H2O (g) → 3H2O (l) (ΔH = -132 kJ/mol) 3H2O (l) → 3H2 (g) + (3/2) O2 (g) (ΔH = 858 kJ/mol)

Explanation: ??

8 0
3 years ago
Calculate [H3O+] and [OH−] for each of the following solutions at 25 ∘C given the pH. pH= 8.74, pH= 11.38, pH= 2.81
Gnom [1K]

Answer:

Explanation:

Given parameters;

pH  = 8.74

pH = 11.38

pH = 2.81

Unknown:

concentration of hydrogen ion and hydroxyl ion for each solution = ?

Solution

The pH of any solution is a convenient scale for measuring the hydrogen ion concentration of any solution.

It is graduated from 1 to 14

      pH = -log[H₃O⁺]

      pOH = -log[OH⁻]

 pH + pOH = 14

Now let us solve;

   pH = 8.74

             since  pH = -log[H₃O⁺]

                           8.74 =  -log[H₃O⁺]

                           [H₃O⁺] = 10⁻^{8.74}

                             [H₃O⁺]  = 1.82 x 10⁻⁹mol dm³

       pH + pOH = 14

                 pOH = 14 - 8.74

                  pOH = 5.26

                  pOH = -log[OH⁻]

                     5.26  = -log[OH⁻]

                     [OH⁻] = 10^{-5.26}

                      [OH⁻] = 5.5 x 10⁻⁶mol dm³

2.  pH = 11.38

             since  pH = -log[H₃O⁺]

                           11.38 =  -log[H₃O⁺]

                           [H₃O⁺] = 10⁻^{11.38}

                             [H₃O⁺]  = 4.17 x 10⁻¹² mol dm³

           pH + pOH = 14

                 pOH = 14 - 11.38

                  pOH = 2.62

                  pOH = -log[OH⁻]

                     2.62  = -log[OH⁻]

                     [OH⁻] = 10^{-2.62}

                      [OH⁻] =2.4 x 10⁻³mol dm³

3. pH = 2.81

             since  pH = -log[H₃O⁺]

                           2.81 =  -log[H₃O⁺]

                           [H₃O⁺] = 10⁻^{2.81}

                             [H₃O⁺]  = 1.55 x 10⁻³ mol dm³

           pH + pOH = 14

                 pOH = 14 - 2.81

                  pOH = 11.19

                  pOH = -log[OH⁻]

                     11.19  = -log[OH⁻]

                     [OH⁻] = 10^{-11.19}

                      [OH⁻] =6.46 x 10⁻¹²mol dm³

5 0
4 years ago
Butene is an alkene explain how you know
ohaa [14]
Because the suffix is -ene. Anything that ends in ene is an alkene.
4 0
3 years ago
How much energy is required to melt 2kg of ice at 0°C?
Ann [662]

Answer  0 °C + Heat required to convert 2 kg of water at 0 °C to 2 kg of water at 20 °C. Therefore, to melt 2 kg of ice 835.48 KJ of heat is required.

7 0
3 years ago
Read 2 more answers
Other questions:
  • Hey help me please :)<br> What is a possible pH of acid rain?<br><br> 7.0<br> 6.9<br> 4.3<br> 10.5
    15·2 answers
  • How does matter change from one state to another?
    5·1 answer
  • Please Help Me What is chromatography? Question 2 options: A) A picture taken with a chrome camera. B) The stationary phase. C)
    9·1 answer
  • How is stoichiometry used to calculate the amount of product from amount of reactant?
    8·2 answers
  • 1. For which of these elements would the first ionization energy of the atom be higher than that of the diatomic molecule?
    5·1 answer
  • Has earth always had the same land masses and oceans that it has today?
    5·1 answer
  • Consider two concentric spheres whose radii differ by t = 1 nm, the "thickness" of the interface. At what radius (in nm) of sphe
    15·1 answer
  • What would happen if you mixed baking soda and milk?
    15·2 answers
  • How many moles of H3PO4 would produce 12 moles of water in this reaction? ЗKOH + H3PO4 K3PO4 + 3H20
    11·2 answers
  • Now consider a sample of the gas at 33 deg C, 744 mm Hg, and 450 mL. If the pressure is decreased to 725 mm Hg and the temperatu
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!