Someone help meeee please

A skateboarder coasts a distance of 20 meters in 4 seconds. What is the person's speed?

yKpoI14uk [10]

Answer:

5

Explanation:

20/4

5 0

2 years ago

You are given two closed containers. Each containing a liquid solvent. Ammonia and table salt will dissolve in container A. Hexa

snow_tiger [21]

Ammonia and table salt dissolves in polar solvents, so A is water,
CO2 and hexane are non-polar substances, so they are going to be dissolved in non-polar solvent, so I think it is going to be carbon tetrachloride

Answer is <span>A) A - water; B - carbon tetrachloride

Table salt does not dissolve in oil and CCl4, and Br2 is too active and it is going to react with NH3.</span>

3 0

2 years ago

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The standard entropy change of a reaction has a positive value. This reaction results in: Select the correct answer below: a dec

Ira Lisetskai [31]

Explanation:

The standard entropy change of a reaction has a positive value. This reaction results in an increase in entropy.

Positive entropy means the system has increased its degree of disorderness.

5 0

2 years ago

The pyrolysis of ethane proceeds with an activation energy of about 300 kJ/mol. How much faster is the decomposition at 625°C th

Alona [7]

Answer:

The decomposition of ethane is 153.344 times much faster at 625°C than at 525°C.

Explanation:

According to the Arrhenius equation,

$K=A\times e^{\frac{-Ea}{RT}}$

$\log (\frac{K_2}{K_1})=\frac{Ea}{2.303\times R}[\frac{1}{T_1}-\frac{1}{T_2}]$

where,

$K_2$ = rate of reaction at $T_2$

$K_1$ = rate of reaction at $T_1$

$Ea$ = activation energy of the reaction

R = gas constant = 8.314 J/K mol

$E_a=300 kJ/mol=300,000 J/mol$

$T_2=625^oC=898.15 K,T_1=525^oC=798.15 K$

$\log (\frac{K_2}{K_1})=\frac{300,000 J/mol}{2.303\times 8.314 J/K mol}[\frac{1}{798.15 K}-\frac{1}{898.15 K}]$

$\log (\frac{K_2}{K_1})=2.185666$

$K_2=153.344\times K_1$

The decomposition of ethane is 153.344 times much faster at 625°C than at 525°C.

4 0

2 years ago

Identify the single displacement reaction. 2H 2 + O 2 ⟶ 2H 2O Al 2S 3 ⟶ 2Al + 3S Cl 2 + 2KBr ⟶ 2KCl + Br 2 C 4H 12 + 7O 2 ⟶ 6H 2

ozzi

Answer: $Cl_2+2KBr\rightarrow 2KCl+Br_2$

Explanation:

A single displacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution. Thus one element should be different from another element.

$Cl_2+2KBr\rightarrow 2KCl+Br_2$

Synthesis reaction is defined as the reaction where substances combine in their elemental state to form a single compound. $2H_2+O_2\rightarrow 2H_2O$

Decomposition reaction is defined as the reaction where a single substance breaks down into two or more simpler substances.

$Al_2S_3\rightarrow 2Al+3S$

Combustion is a type of chemical reaction in which hydrocarbons burn in the presence of oxygen to form carbon dioxide and water along with heat.

$C_4H_{12}+7O_2\rightarrow 6H_2O+4CO_2$

6 0

3 years ago