Ask question

Ask question

All categories

2 years ago

7

HELP PLZ!!! A sample contains only the compound CaCl2 and water. When it is dried, its weight decreases from 5.00g to 4.24g. Wha

t is the mass percentage of water in the original sample? Round to three significant figures.

2 answers:

steposvetlana [31]2 years ago

7 0

Answer:

Mass of water is 18.01528 g/mol. I hope this helps

Explanation:

AfilCa [17]2 years ago

5 0

Answer:is 15.2%

Explanation:

Got it wrong and this the correct answer it told me

You might be interested in

a sample of 0.0084 mol of HCl is dissolved in water to make a 1500 mL solution. calculate the molar it’s of the HCl solution, Th

Allisa [31]

Answer:

pH = 2.25

Explanation:

pH is a measurement in chemistry defined as the -log [H₃O⁺]. Molarity [], is defined as the ratio between moles of solute (HCl) and the liters of solution

To solve this question we must find the molarity of the H₃O⁺ knowing: [HCl] = [H₃O⁺]

[HCl]:

0.0084moles / 1.500L

= 0.0056M = [HCl] = [H₃O⁺]

pH = -log [H₃O⁺] = -log [0.0056M]

<h3>pH = 2.25</h3>

7 0

2 years ago

Using the equations 2 Sr(s) + O₂ (g) → 2 SrO (s) ∆H° = -1184 kJ/mol SrO (s) + CO₂ (g) → SrCO₃ (s) ∆H° = -234 kJ/mol CO₂ (g) → C(

kkurt [141]

<u>Answer:</u> The $\Delta H^o_{rxn}$ for the reaction is 72 kJ.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

$2SrCO_3(s)\rightarrow 2Sr(s)+2C(s)+3O_2(g)$ $\Delta H^o_{rxn}=?$

The intermediate balanced chemical reaction are:

(1) $2Sr(s)+O_2(g)\rightarrow 2SrO(s)$ $\Delta H_1=-1184kJ$

(2) $SrO(s)+CO_2(g)\rightarrow SrCO_3(s)$ $\Delta H_2=-234kJ$ ( × 2)

(3) $CO_2(g)\rightarrow C(s)+O_2(g)$ $\Delta H_3=394kJ$ ( × 2)

The expression for enthalpy of the reaction follows:

$\Delta H^o_{rxn}=[1\times (\Delta H_1)]+[2\times (-\Delta H_2)]+[2\times (\Delta H_3)]$

Putting values in above equation, we get:

$\Delta H^o_{rxn}=[(1\times (-1184))+(2\times -(-234))+(2\times (394))]=72kJ$

Hence, the $\Delta H^o_{rxn}$ for the reaction is 72 kJ.

4 0

2 years ago

Andrew plays trumpet in the concert band. He holds the trumpet still at his side until it is time for him to play. When it is ti

Tom [10]

Answer:

Explanation:

The first law is An object won't move by itself, and once in motion, it won't stop unless some force acts upon it. With this being said when the trumpet is at his side and he is not holding it will not move not until he lets go of it.

6 0

2 years ago

Read 2 more answers

Aqueous hydrobromic acid reacts with solid sodium hydroxide to produce aqueous sodium bromide and liquid water . If of sodium br

Roman55 [17]

Answer:

The percentage yield is 50%

7 0

2 years ago

A solution with [ OH] of 5 x 10-3 has a pH of

CaHeK987 [17]

Answer:

11·699

Explanation:

Given the concentration of hydroxide ion in the solution is 5 × $10^{-3}$ M

Assuming the temperature at which it is asked to find the pH of the solution be 298 K

<h3>At 298 K the dissociation constant of water is $10^{-14}$ </h3><h3>∴ pH + pOH = 14 at 298 K</h3><h3>pOH of the solution = -log( concentration of hydroxide ion )</h3>

∴ pOH of the given solution = - log(5 × $10^{-3}$ = -0·699 + 3 = 2·301

pH of the given solution = 14 - 2·301 = 11·699

∴ pH of the solution = 11·699

8 0

2 years ago