Butanoic acid + 2 propanol

In one experiment, magnesium metal melts. In a second experiment, magnesium metal ignites as it combines with oxygen. Classify t

joja [24]

Answer:

magnesium metal melts = physical change

magnesium metal ignites = chemical change

Explanation:

Physical changes are those in which the identity of the subtance remains unaltered. No new compounds are formed. They involve generally changes in agreggation states of matter: solid, liquid or gas. The first experiment, in which magnesium metal melts is a physical change because it only changes the state of matter, from solid to liquid, but it is still magnesium metal.

Conversely, chemical changes involve atoms combinations to form new compounds. The second experiment, in which magnesium metal ignites, is a chemical change. After the change, magnesium metal is no longer the metal but a metal oxide.

8 0

3 years ago

The equilibrium constant, Kc, for the following reaction is 5.10×10-6 at 548 K. NH4Cl(s) NH3(g) + HCl(g) Calculate the equilibri

levacccp [35]

Answer: The equilibrium concentration of HCl is $2.26\times 10^{-3}M$

Explanation:

We are given:

Moles of $NH_4Cl(s)$ = 0.564 moles

Volume of vessel = 1.00 L

Molarity is calculated by using the equation:

$\text{Molarity}=\frac{\text{Number of moles}}{\text{Volume of solution (in L)}}$

Molarity of $NH_4Cl=\frac{0.564}{1}=0.564M$

The given chemical equation follows:

$NH_4Cl(s)\rightleftharpoons NH_3(g)+HCl(g)$

Initial: 0.564

At eqllm: 0.564-x x x

The expression of $K_c$ for above equation follows:

$K_c=[NH_3][HCl]$

The concentration of pure solid and pure liquid is taken as 1.

We are given:

$K_c=5.10\times 10^{-6}$

Putting values in above equation, we get:

$5.10\times 10^{-6}=x\times x\\\\x=2.26\times 10^{-3}M,-2.26\times 10^{-3}M$

Negative sign is neglected because concentration cannot be negative.

So, $[HCl]=2.26\times 10^{-3}M$

Hence, the equilibrium concentration of HCl is $2.26\times 10^{-3}M$

5 0

3 years ago

Consider the following balanced reaction. How many grams of water are required to form 75.9 g of HNO3? Assume that there is exce

Iteru [2.4K]

Answer:

10.85 g of water

Explanation:

First we write the balanced chemical equation

$3NO_{2} +H_{2}O -->2HNO_{3} +NO$

Then we calculate the number of moles of nitric acid produced

n(HNO3) = $\frac{mass}{molar mass} =\frac{75.9g}{63.02g/mol}=1.2044 mol$

According to the balanced equation, water needed in moles is always half the number of moles of HNO3 produced. So since we will produce 1.2044 mol of HNO3, we will need 0.6022 mol of water. Now to calculate what mass that is:

mass(water)=number of moles*molar mass=0.6022mol*18.02g/mol=10.85g

5 0

3 years ago

-QUESTION 5-

vodomira [7]

The tall trees much of the sun
have you ever been in a forest? if you have, you’ve probably noticed that it’s usually very shady, and not a lot of sunlight hits the ground. That’s cause the tall trees are so dense, the sunlight doesn’t reach the ground

5 0

2 years ago

A 30.0-g piece of metal at 203oC is dropped into 400.0 g of water at 25.0 oC. The water temperature rises to 29.0 oC. Calculate

oee [108]

The specific heat of the metal is 2.4733 J/g°C.

Given the following data:

Initial temperature of water = 25.0°C

Final temperature of water = 29.0°C

Mass of water = 400.0 g

Mass of metal = 30.0 g

Temperature of metal = 203.0°C

We know that the specific heat capacity of water is 4.184 J/g°C.

To find the specific heat of the metal (J/g°C):

Heat lost by metal = Heat gained by water.

$Q_{metal} = Q_{water}$

Mathematically, heat capacity or quantity of heat is given by the formula;

$Q = mc\theta$

Where:

Q is the heat capacity or quantity of heat.

m is the mass of an object.

c represents the specific heat capacity.

∅ represents the change in temperature.

Substituting the values into the formula, we have:

$30(203)c = 400(4.184)(29 \; -\; 20)\\\\6090c = 1673.6(9)\\\\6090c = 15062.4\\\\c = \frac{15062.4}{6090}$

Specific heat capacity of metal, c = 2.4733 J/g°C

Therefore, the specific heat of the metal is 2.4733 J/g°C.

8 0

2 years ago