Scientific notation of 2/10

What are the correct coefficients for the reaction below:

77julia77 [94]

C was the answer i had and it was right

7 0

3 years ago

50 POINTS

Luba_88 [7]

The answer is D. easier, higher

5 0

2 years ago

Read 2 more answers

A particle of mass 2.0 kg moves under the influence of the force F(x)=(-5x^2+7x)~\text{N}F(x)=(−5x 2 +7x) N. If its speed at

Brums [2.3K]

Answer:

The speed of the particle at x = 4.0 m is 13.66 m/s

Explanation:

The work done by this force between the two points above is given by

W = ∫ F dx

W = ∫⁴₋₄ (-5x² + 7x) dx

W = [(-5x³/3) + (7x²/2)]⁴₋₄

W = [(-5(4³)/3) + (7(4²)/2)] - [(-5(-4)³)/3) + (7((-4)²)/2)] = (-50.6667) - (162.6667) = (- 213.33 J)

Kinetic energy at -4.0 m

At this point, v = 20 m/s

K.E = mv²/2 = 2 × 20²/2 = 400 J

To obtain the kinetic energy at 4 m,

We apply the work-energy theorem which mathematically translates to

The work done in moving a particle from one point to another = Change in kinetic energy of the particle between those two points

W = ΔK.E

Work done between x = - 4m and x = 4 m is - 213.33 J

Hence, ΔK.E = -213.33 J

Change in kinetic energy of the particle between x = - 4m and x = 4m is ΔK.E

ΔK.E = (Kinetic energy at x = 4m) - (kinetic energy at x = - 4m)

- 213.33 J = (mv²/2) - 400

mv²/2 = -213.33 + 400 = 186.67 J

2v² = 2 × 186.67

v² = 186.67

v = 13.66 m/s.

5 0

3 years ago

g When 2.50 g of methane (CH4) burns in oxygen, 125 kJ of heat is produced. What is the enthalpy of combustion (in kJ) per mole

Anna [14]

Answer:

-800 kJ/mol

Explanation:

To solve the problem, we have to express the enthalpy of combustion (ΔHc) in kJ per mole (kJ/mol).

First, we have to calculate the moles of methane (CH₄) there are in 2.50 g of substance. For this, we divide the mass into the molecular weight Mw) of CH₄:

Mw(CH₄) = 12 g/mol C + (1 g/mol H x 4) = 16 g/mol

moles CH₄ = mass CH₄/Mw(CH₄)= 2.50 g/(16 g/mol) = 0.15625 mol CH₄

Now, we divide the heat released into the moles of CH₄ to obtain the enthalpy per mole of CH₄:

ΔHc = heat/mol CH₄ = 125 kJ/(0.15625 mol) = 800 kJ/mol

Therefore, the enthalpy of combustion of methane is -800 kJ/mol (the minus sign indicated that the heat is released).

3 0

2 years ago

0.352 g sample of a diprotic acid is dissolved in water and titrated with 0.150 M NaOH.0.150 M NaOH. What is the molar mass of t

Aliun [14]

<h3>Answer:</h3>

128.94 g/mol

<h3>Explanation:</h3>

Given;

Mass of diprotic acid, H₂X =0.352 g

Molarity of NaOH = 0.150 M

Volume of the NaOH = 36.4 mL

We are required to calculate the molar mass of the acid.

Note: A diprotic acid is an acid that contains 2 replaceable hydrogen atoms

<h3>Step 1: Write the balanced equation fro the reaction;</h3>

The balanced equation for the reaction between the diprotic acid and NaOH will be;

H₂X(aq) + 2NaOH(aq) → Na₂X(aq) + 2H₂O(l)

<h3>Step 2: Determine the number of moles of NaOH used </h3>

Given the molarity and volume of NaOH we can calculate the number of moles;

Moles of NaOH = Molarity × Volume

= 0.150 M × 0.0364 L

= 0.00546 moles

<h3>Step 3: Use the mole ratio to determine moles of the acid </h3>

From the equation;

1 mole of the acid reacts with 2 moles of NaOH

Therefore; H₂x : NaOH = 1 : 2

Moles of H₂x = 0.00546 moles ÷ 2

= 0.00273 moles

<h3>Step 4: Determine the molar mass of the acid.</h3>

Molar mass is the mass equivalent to 1 mole of a compound or element

From our calculations;

0.00273 moles = 0.352 g of the acid;

Therefore, mass in 1 mole ;

= 0.352 g ÷ 0.00273 moles

= 128.94 g/mol

Thus, the molar mass of the diprotic, H₂X is 128.94 g/mol

7 0

3 years ago