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4 years ago

Atom tableTomic number mass number number of protons number of neutrons number of electrons symbol

Chemistry

1 answer:

Finger [1]4 years ago

8 0

Answer:

Atomic number mass is big number underneath and number of proton on the right side of a proton and number of neutron is mass - proton and number of electron with bohr digram or outer shell

Explanation:

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Calculate the molarity of a solution obtained dissolving 10.0 g of cobalt(Ⅱ) bromide tetrahydrate in enough water to make 450 mL

Vladimir [108]

Answer:

The molarity of the CoBr2•4H2O solution is 7.64 × 10-2 M

Explanation:

Cobalt (II) bromide tetrahydrate

• Cobalt - A transition metal with Roman numeral (II) → charge: +2 → Co2+

• Bromide - anion from group 7A → -1 charge → symbol: Br-

• Tetrahydrate- tetra- means 4 and hydrate is H2O

The chemical formula of the compound is: CoBr2•4H2O

We then need to determine the number of moles of CoBr2•4H2O since this is the only information missing for us to find molarity. Notice that the volume of the solution is already given.

We’re given the mass of CoBr2•4H2O. We can use the molar mass of CoBr2•4H2O4 to find the moles.

•The molar mass of CoBr2•4H2O is:

CoBr2•4H2O

1 Co x 58.93 g/mol Co = 58.93 g/mol

2 Br x 79.90 g/mol Br = 159.80 g/mol

8 H x 1.008 g/mol H = 8.064 g/mol

4 O x 16.00 g/mol O = 64.00 g/mol

________________________________________

Sum = 290.79 g/ mo

The moles of CoBr2•4H2O is:

= 10.0 g CoBr2•4H2O x $\frac{ 1 mol CoBr_2 . 4H_2O}{290.79 g CoBr_2 . 4H_2O}$

= 0.0344 mol CoBr2•4H

We know that the volume of the solution is 450 mL.

We can now calculate for molarity:

Convert mL to L → 1 mL = 10-3 L

Formula:

Molarity (M)= Mole of solute / Liters of solution

= 0.0344 mol CoBr2•4H / 450 mL x 1 ml / 10^ -3 L

= 0.0764

= 7.64 × 10-2 mol/L

8 0

4 years ago

The pka of hf is 3.2 determine the pkb of hf?

Julli [10]

Well, first we must remember that

$pK_{a}+pK_{b}=14$

This is because

$K_{a}*K_{b}=10^{-14}$

$-log(K_{a}*K_{b})=-log(10^{-14})\\-logK_{a}+-logK_{b}=-log(10^{-14})\\pK_{a}+pK_{b}=14$

So then

$pK_{b}=14-pK_{a}=14-3.2=1.8$

7 0

4 years ago

Read 2 more answers

Help plz. ASAP!!!!

GuDViN [60]

Answer:

Option A, 931 Kg

Explanation:

As we know that weight is equal to the product of mass and acceleration due to gravity.

Thus,

$W = M * 9.8$ m/s2

Substituting the given values in above equation, we get -

$W = 95 * 9.8 \\W = 931$ Kg

Hence, option A is correct

4 0

3 years ago

Is 2 C4H10 + 13 O2 → 8 CO2 + 10 H2O a double replacement?

natulia [17]

Answer:

The answer to your question is No, it is not.

Explanation:

Data

C₄H₁₀ + 13O₂ ⇒ 8CO₂ + 10H₂O

In a double replacement reaction, two reactants interchange cations an example of these reactions are neutralization reactions. In neutralization reactions, an acid and a base react to form a salt and water.

The reaction of this problem is not a double replacement reaction because the products are carbon dioxide and water, not a salt and water.

The reaction of this problem is a combustion reaction.

8 0

4 years ago

Calculate the mass of glucose metabolized by a 60.0 −kg person in climbing a mountain with an elevation gain of 1550 m . Assume

lbvjy [14]

Answer:

Mass of glucose = 515.34 g

Explanation:

We are given;

Mass; m = 60 kg

Elevation; h = 1550 m

Acceleration due to gravity; 9.8 m/s²

Now, work performed to lift 60kg by 1550m is given by the formula;

W = mgh

W = 60 × 9.8 × 1550

W = 911400 J

We are told the actual work is 4 times the one above.

Thus;

Actual work = 4W = 4 × 911400 = 3,645,600 J

Now,

Molar mass of Glucose(C6H12O6) = 180 g/mol

We are given standard enthalpy of combustion = -1273.3 KJ/mol = -1273300

Moles of glucose = 3645600/1273300 = 2.863mol

Mass of glucose = 2.863 mol × 180 g/mol

Mass of glucose = 515.34 g

4 0

4 years ago