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AleksAgata [21]

2 years ago

7

Suppose you are riding a bicycle. Describe a situation in which the bicycle has balanced forces acting on it. Describe a situati

on in which unbalanced forces are acting on it.
Text to speech

1 answer:

vladimir2022 [97]2 years ago

4 0

balanced: there is one person on the bike with both feet on both pedals going at a steady pace

unbalanced: there is one person on the bike with both feet to one side of the bike swaying from side to side

balanced: there are two people on the bike with both feet on both sides and theyre both moving the same way

unbalanced: there are two people on the bike with their feet to one side and theyre not moving in the same way together

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Tare the balance. Put calorimeter (no lid) on the balance.

Paladinen [302]

Answer:12.46 g

Explanation:

3 0

2 years ago

Why are the electrons in a nitrogen-phosphorus covalent bond not shared equally? which atom do the electrons spend more time aro

a_sh-v [17]

<span>Electrons in a nitrogen-phosphorus covalent bond are not shared equally because nitrogen and phosphorus do not have the same electronegativity. The atoms spend more time around the most electronegative atom nitrogen.</span>

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2 years ago

Platinum, which is widely used as a catalyst, has a work function φ(the minimum energy needed to eject an electron from the meta

Arlecino [84]

Answer:

A. $\lambda_0=2.196\times 10^{-7}\ m$

Explanation:

The work function of the Platinum = $9.05\times 10^{-19}\ J$

For maximum wavelength, the light must have energy equal to the work function. So,

$\psi _0=\frac {h\times c}{\lambda_0}$

Where,

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

c is the speed of light having value $3\times 10^8\ m/s$

$\lambda_0$ is the wavelength of the light being bombarded

$\psi _0=Work\ function$

Thus,

$9.05\times 10^{-19}=\frac {6.626\times 10^{-34}\times 3\times 10^8}{\lambda_0}$

$\frac{9.05}{10^{19}}=\frac{19.878}{10^{26}\lambda_0}$

$9.05\times \:10^{26}\lambda_0=1.9878\times 10^{20}$

$\lambda_0=2.196\times 10^{-7}\ m$

8 0

2 years ago

2CH4(g)⟶C2H4(g)+2H2(g)

Rasek [7]

Answer : The enthalpy change for the reaction is, 201.9 kJ

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The balanced reaction of $CH_4$ will be,

$2CH_4(g)\rightarrow C_2H_4(g)+2H_2(g)$ $\Delta H^o=?$

The intermediate balanced chemical reaction will be,

(1) $CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(l)$ $\Delta H_1=-890.3kJ$

(2) $C_2H_4(g)+H_2(g)\rightarrow C_2H_6(g)$ $\Delta H_2=-136.3kJ$

(3) $2H_2(g)+O_2(g)\rightarrow 2H_2O(l)$ $\Delta H_3=-571.6kJ$

(4) $2C_2H_6(g)+7O_2(g)\rightarrow 4CO_2(g)+6H_2O(l)$ $\Delta H_4=-3120.8kJ$

Now we will multiply the reaction 1 by 2, revere the reaction 2, reverse and half the reaction 3 and 4 then adding all the equations, we get :

(1) $2CH_4(g)+4O_2(g)\rightarrow 2CO_2(g)+4H_2O(l)$ $\Delta H_1=2\times (-890.3kJ)=-1780.6kJ$

(2) $C_2H_6(g)\rightarrow C_2H_4(g)+H_2(g)$ $\Delta H_2=-(-136.3kJ)=136.3kJ$

(3) $H_2O(l)\rightarrow H_2(g)+\frac{1}{2}O_2(g)$ $\Delta H_3=-\frac{1}{2}\times (-571.6kJ)=285.8kJ$

(4) $2CO_2(g)+3H_2O(l)\rightarrow C_2H_6(g)+\frac{7}{2}O_2(g)$ $\Delta H_4=-\frac{1}{2}\times (-3120.8kJ)=1560.4kJ$

The expression for enthalpy of the reaction will be,

$\Delta H^o=\Delta H_1+\Delta H_2+\Delta H_3+\Delta H_4$

$\Delta H=(-1780.6kJ)+(136.3kJ)+(285.8kJ)+(1560.4kJ)$

$\Delta H=201.9kJ$

Therefore, the enthalpy change for the reaction is, 201.9 kJ

5 0

2 years ago

A beaker has 0.2 M of Na2SO4. What will be the concentration of sodium and sulfate ions?

netineya [11]

The concentration of sodium and sulphate ions are [ $Na^+$ ] = 0.4 M, [ $SO_4^2-$ ] = 0.2 M

Explanation:

The molar concentration is defined as the number of moles of a molecule or an ion in 1 liter of a solution.

In the given solution, the concentration of the salt sodium sulphate is 0.2M. So, 0.2 moles of sodium sulphate is present in 1 liter of solution.

Assuming 100% dissociation,

1 molecule of sodium sulphate gives 2 ions of sodium and 1 ion of sulphate.

So 0.2 moles of sodium sulphate will give 0.4 moles of sodium ions and 0.2 moles of sulphate ions.

7 0

2 years ago