All categories

2 years ago

List four observations that suggest chemical change is occurring

Chemistry

1 answer:

allsm [11]2 years ago

8 0

Answer:

Examples of Chemical Changes

Burning wood.

Souring milk.

Mixing acid and base.

Digesting food.

Cooking an egg.

Heating sugar to form caramel.

Baking a cake.

Rusting of iron.

You might be interested in

Which characteristic of planets depends upon its distance from the Sun?

Svetradugi [14.3K]

Answer:

I think its the length of its year

8 0

2 years ago

Read 2 more answers

What is the density of chlorine gas (MM = 71.0glmol) at 1.50 atm and 25.0C

IrinaVladis [17]

Answer: D=4.35g/L

Explanation:

The formula for density is $D=\frac{M}{V}$ . M is mass in grams and V is volume in liters.

Since we are give pressure and temperature, we can use the ideal gas law to find moles/volume. FInding moles/volume would give us the base for density. All we would have to do is convert moles to grams.

Ideal Gas Law: PV=nRT

$\frac{n}{V} =\frac{P}{RT}$

$\frac{n}{V}=\frac{1.50 atm}{(0.08206Latm/Kmol)(25+274.15K)}$

$\frac{n}{V} =\frac{0.061309mol}{L}$

Now that we have moles, we can use molar mass of chlorine gas to find grams.

$0.061309mol*\frac{71.0g}{mol} =4.3529g$

With our grams, we can find our density.

$D=\frac{4.3529g}{L}$

We need correct significant figures so our density is:

$D=\frac{4.35g}{L}$

5 0

3 years ago

The nucleoside adenosine exists in a protonated form with a pKa of 3.8. The percentage of the protonated form at pH 4.8 is close

Natasha_Volkova [10]

Answer:

Ok:

Explanation:

So, you can use the Henderson-Hasselbalch equation for this:

pH = pKa + log( $A^-/HA$ ) where A- is the conjugate base of the acid. In other words, A- is the deprotonated form and HA is the protonated.

We can solve that

1 = log( $A^-/HA\\$ ) and so 10 = $A^-/HA$ or 10HA = A-. For every 1 protonated form of adenosine (HA), there are 10 A-. So, the percent in the protonated form will be 1(1+10) or 1/11 which is close to 9 percent.