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2 years ago

What is the amount of heat released by 1.00 gram of liquid water at 0°C when it changes to 1.00 gram of ice at 0°C?

Chemistry

1 answer:

QveST [7]2 years ago

8 0

Answer:

334J/g

Explanation:

Data obtained from the question include:

Mass (m) = 1g

Specific heat of Fusion (Hf) = 334 J/g

Heat (Q) =?

Using the equation Q = m·Hf, we can obtain the heat released as follow:

Q = m·Hf

Q = 1 x 334

Q = 334J

Therefore, the amount of heat released is 334J

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A bottle containing 1,665 g of sulfuric acid (H2SO4, 98.08 g/mol) was spilled in a laboratory. The emergency spill kit contained

Tamiku [17]

Answer:

A. Yes, there is more than enough sodium carbonate.

Explanation:

Hello,

In this case, based on the given reaction which is:

$H_2SO_4(aq) + Na_2CO_3(s) \rightarrow Na_2SO_4(aq) + CO_2(g) + H_2O(l)$

By stoichiometry, one computes the grams of sodium carbonate that will neutralize 1,665 g of sulfuric acid as shown below:

$1,665gH_2SO_4*\frac{1molH_2SO_4}{98.08gH_2SO_4}*\frac{1molNa_2CO_3}{1molH_2SO_4} *\frac{105.99gNa_2CO_3}{1molNa_2CO_3}*\frac{1kgNa_2CO_3}{1000gNa_2CO_3}\\m_{Na_2CO_3}=1.80gNa_2CO_3$

Thus, the available mass is 2.0 kg so 0.2 kg are in excess, therefore: A. Yes, there is more than enough sodium carbonate.

Best regards.

5 0

2 years ago

Picric acid has been used in the leather industry and in etching copper. However, its laboratory use has been restricted because

olchik [2.2K]

Answer:

0.3023 M

Explanation:

Let Picric acid = $H_{picric}$

So, $H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

The ICE table can be given as:

$H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

Initial: 0.52 0 0

Change: - x + x + x

Equilibrium: 0.52 - x + x + x

Given that;

acid dissociation constant ( $K_a$ ) = 0.42

$K_a = \frac{[H_3O^+][Picric^-]}{H_{picric}}$

$0.42 = \frac{[x][x]}{0.52-x}}$

$0.42 = \frac{[x]^2}{0.52-x}}$

0.42(0.52-x) = x²

0.2184 - 0.42x = x²

x² + 0.42x - 0.2184 = 0 -------------------- (quadratic equation)

Using the quadratic formula;

$\frac{-b+/-\sqrt{b^2-4ac} }{2a}$ ; ( where +/- represent ± )

= $\frac{-0.42+/-\sqrt{(0.42)^2-4(1)(-0.2184)} }{2*1}$

= $\frac{-0.42+/-\sqrt {0.1764+0.8736} }{2}$

= $\frac{-0.42+\sqrt {1.0496} }{2}$ OR $\frac{-0.42-\sqrt {1.0496} }{2}$

= $\frac{-0.42+1.0245}{2}$ OR $\frac{-0.42-1.0245}{2}$

= $\frac{0.6045}{2}$ OR $-\frac{1.4445}{2}$

= 0.30225 OR - 0.72225

So, we go by the +ve integer that says:

x = 0.30225

x = [ $H_3}O^+$ ] = [ $Picric^-$ ] = 0.3023 M

∴ the value of [H3O+] for an 0.52 M solution of picric acid = 0.3023 M (to 4 decimal places).

6 0

2 years ago

Nuclear power plants produce energy using fission. One common fuel, uranium-235, produces energy through the fission reaction 23

Vikentia [17]

Answer:

mass of U-235 = 15.9 g (3 sig. figures)

Explanation:

1 atom can produce -------------------------> 3.20 x 10^-11 J energy

x atoms can produce ----------------------> 1.30 x 10^12 J energy

x = 1.30 x 10^12 / 3.20 x 10^-11

x = 4.06 x 10^22 atoms

1 mol ----------------------> 6.023 x 10^23 atoms

y mol ----------------------> 4.06 x 10^22 atoms

y = 0.0675 moles

mass of U-235 = 0.0675 x 235 = 15.8625

mass of U-235 = 15.9 g (3 sig. figures)

7 0

2 years ago

What mass (g) of barium iodide is contained in 188 ml of a barium iodide solution that has an iodide ion concentration of 0.532m

Katarina [22]

Answer:

What mass (g) of barium iodide is contained in 188 mL of a barium iodide solution that has an iodide ion concentration of 0.532 M?

A) 19.6

B) 39.1

C) 19,600

D) 39,100

E) 276

The correct answer to the question is

B) 39.1 grams

Explanation:

To solve the question

The molarity ratio is given by

188 ml of 0.532 M solution of iodide.

Therefore we have number of moles = 0.188 × 0.532 M = 0.100016 Moles

To find the mass, we note that the Number of moles = $\frac{Mass}{Molar Mass}$ from which we have

Mass = Number of moles × molar mass

Where the molar mass of Barium Iodide = 391.136 g/mol

= 0.100016 moles ×391.136 g/mol = 39.12 g

8 0

2 years ago

emelie is working on a science project. her task is to answer the question does rogooti a hair cream sold on tv affect the speed

joja [24]

Answer:

This question is incomplete and unclear; the complete question including the missing part is:

Emelie is working on a science project. Her task is to answer the question:

"Does Rogooti (a hair cream sold on TV) affect the speed of hair growth

(in length)". Her family is willing to volunteer for the experiment. Identify the control group (CG) and the independent and dependent variables.

ANSWER:

Independent variable: Rogooti hair cream

Dependent variable: Speed of hair growth/length

Control group: Family members that do not use the Rogooti hair cream

Explanation:

In an experiment, the independent variable is the variable that the experimenter changes or manipulates in order to bring about a measurable response. In this case, the ROGOOTI HAIR CREAM is the independent variable.

Dependent variable refers to the variable that is measured or the variable that responds to the change made to the independent variable. In this case, the dependent variable is SPEED AT WHICH HAIR GROWS (IN LENGTH).

Control group in an experiment is the group that does not receive the experimental treatment. In this case, the experimental treatment is the Rogooti hair cream, hence, the control group will be the VOLUNTEER FAMILY MEMBERS THAT DOES NOT RECEIVE THE ROGOOTI HAIR CREAM ON THEIR HAIR.

6 0

2 years ago