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3 years ago

What is the mass of a cube of aluminum that is 3.0 cm on each edge? The density of aluminum is 2.7 g/cm3.

Chemistry

1 answer:

n200080 [17]3 years ago

8 0

Do you know the formula? I can’t find it.

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What is the pH of a solution that has a pOH of 5.9

Stella [2.4K]

Answer:

pH = 8.1

Explanation:

Assuming that we are at 25 degrees Celsius, pH + pOH = 14.

We can then plug in the given pOH and solve for pH:

pH + pOH = 14

pH + 5.9 = 14

pH = 14 - 5.9 = 8.1

7 0

3 years ago

You are instructed to create 900. mL of a 0.29 M phosphate buffer with a pH of 7.8. You have phosphoric acid and the sodium salt

Aleksandr [31]

Answer:

B and C

Explanation:

When we have to do a buffer solution we always have to choose the reaction that has the pKa closer to the desired pH value. When we find the pKa values we will obtain:

$pKa_1=-Log[6.9x10^-^3]=2.16$

$pKa_2=-Log[6.2x10^-^8]=7.20$

$pKa_3=-Log[4.8x10^-^13]=12.31$

The closer value is pKa2 with a value of 7.2. Therefore we have to use the second reaction. In which $H_2PO_4^-^1$ is the acid and $HPO_4^-^2$ is the base. Therefore the answer for the first question is B and the answer for the second question is C.

8 0

3 years ago

A gas occupies 800ml at a temperature of 27C. What is the volume at 132C?

pishuonlain [190]

V
1

/T
1

=V
2

/T
2

(900.0 mL) / (300.0 K) = (x) / (405.0 K); x = 1215 mL.

Change the 900 to 800, and the 300 to 27, then change the 405 to 132. And solve

3 0

3 years ago

Wich of these equations are balanced? a) H2SO4+2AL--->AL2(SO4) b)2KCL+Pb(NO3)2--->2KNO3+PbCL2

Zolol [24]

The answer is b since on a it says H2 but on the right side there is no H idk if you forgot to put H there so im guessing b. Have a good day

4 0

3 years ago

Consider this reaction:

Brilliant_brown [7]

Answer : The oxidation state of Mg in Mg(s) is (0).

Explanation :

Oxidation number or oxidation state : It represent the number of electrons lost or gained by the atoms of an element in a compound.

Oxidation numbers are generally written with the sign (+) and (-) first and then the magnitude.

Rules for Oxidation Numbers are :

The oxidation number of a free element is always zero.

The oxidation number of a monatomic ion equals the charge of the ion.

The oxidation number of Hydrogen (H) is +1, but it is -1 in when combined with less electronegative elements.

The oxidation number of oxygen (O) in compounds is usually -2.

The oxidation number of a Group 17 element in a binary compound is -1.

The sum of the oxidation numbers of all of the atoms in a neutral compound is zero.

The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.

The given chemical reaction is:

$Mg(s)+2H_2O(l)\rightarrow Mg(OH)_2(s)+H_2(g)$

In the given reaction, the oxidation state of Mg in Mg(s) is (0) because it is a free element and the oxidation state of Mg in $Mg(OH)_2$ is (+2).

Hence, the oxidation state of Mg in Mg(s) is (0).

3 0

3 years ago