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3 years ago

Round to 4 significant figures: 42,561

Chemistry

1 answer:

arsen [322]3 years ago

7 0

6 is the fourth significant figures

if the number behind it is 5 or more then 5, you must add 1 to the number and ALL the number behind it will turn into 0

so that the answer is 42560

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put the following in order from LARGEST TO SMALLEST nuclueus,molecule,electron,atom,proton and a teacher

SVETLANKA909090 [29]

Answer:

electron, proton, nucleus, atom, molecule teacher

3 0

3 years ago

"acid is responsible for the odor in rancid butter. a solution of 0.25 m butyric acid has a ph of 2.71. what is the ka for"

Salsk061 [2.6K]

Answer:- The Ka for the acid is $1.53*10^-^5$ .

Solution:- In general, monoprotic acid could be represented by HA. The dissociation equation for the ionization of HA is written as:

HA(aq)\rightarrow H^+(aq) + A^-(aq)

Now, we make the ice table for this equation as:

HA(aq)\rightarrow H^+(aq) + A^-(aq)

I 0.25 0 0

C -X +X +X

E (0.25 - X) X X

where, I stands for initial concentration, C stands for change in concentration and E stands for equilibrium concentration.

X is the change in concentration and from ice table it's same as the concentration of hydrogen ion that is calculated from given pH.

$Ka = [H^+][A^-]\frac{1}{HA}$

Where, Ka is the acid ionization constant. Let's plug in the values.

$Ka = \frac{X^2}{0.25-X}$

Let's calculate the value of X first using the equation:

$pH = -log[H^+]$ [/tex]

on taking antilog ob above equation we get:

$[H^+]=10^-^p^H$

$[H^+]=10^-^2^.^7^1$

$[H^+]$ = 0.00195

So, X = 0.001195

Let's plug in this value of X in the equation:-

$Ka=\frac{(0.00195)^2}{0.25-0.00195}$

$Ka=1.53*10^-^5$

So, the value of Ka for butyric acid is $1.53*10^-^5$ .

8 0

3 years ago

Read 2 more answers

The positive sign of the energy difference in a chemical reaction would indicate that ..........

trasher [3.6K]

Answer:

B) the chemicals are gaining energy from the surroundings.

Explanation:

The positive sign of the energy difference in a chemical reaction would indicate that the chemicals are gaining energy from the surroundings. This is what happens in an endothermic reaction.

In an endothermic reaction, heat is absorbed from the surroundings hence the surrounding becomes colder at the end of the changes.

Here the energy change is assigned a positive value.
This is because the heat energy level of the final state is higher than that of the initial state.
So, the difference gives a positive value.

3 0

3 years ago

what is the balanced equation for the reaction of solid magnesium metal with oxygen gas to produce solid magnesium oxide

GaryK [48]

Answer:

2Mg + O₂ ⟶ 2MgO

Explanation:

Step 1. Start with the most complicated-looking formula (O₂?).

Put a 1 in front of it.

Mg + 1O₂ ⟶ MgO

Step 2. Balance O.

We have fixed 2 O on the left. We need 2O on the right. Put a 2 in front of MgO.

Mg + 1O₂ ⟶ 2MgO

Step 3. Balance Mg.

We have fixed 2 Mg on the right-hand side. We need 2 Mg atoms on the left. Put a 2 in front of Mg.

2Mg + 1O₂ ⟶ 2MgO

Every formula now has a coefficient. The equation should be balanced. Let’s check.

Atom On the left On the right

Mg 2 2

O 2 2

All atoms are balanced.

The balanced equation is

2Mg + O₂ ⟶ 2MgO

4 0

3 years ago

Can anyone please help with this!!

Sphinxa [80]

Answer:

2341, last option is the correct choice.

Explanation:

Boiling points of the given compounds are given as:

$CH_4=-161.5\:C^{\circ}\\\\C_4H_{10}=-1\:C^{\circ}\\\\CH_2Cl_2=39.6\:C^{\circ}\\\\H_2O=100\:C^{\circ}$

Best Regards!

5 0

3 years ago