Shawn wants to buy a pair of gloves online. She needs to

Elements that’s are gases, brittle & poor conductors at room temperature are

vlabodo [156]

I think the answer is C for this question

5 0

2 years ago

You will be using the observations given in the scenarios i - vi below to determine which of the following is true for G (a - c)

WITCHER [35]

Answer:

A spontaneous reaction is taking place in a flask. When you touch the flask, it feels cold and gets colder as the reaction progresses........(c,f,g)

A spontaneous reaction is taking place in a flask as evidenced by the formation of gas bubbles. When you touch the flask, it feels hot and gets hotter as the reaction progresses.... (c,d,h)

A spontaneous reaction is taking place in a flask. When you touch the flask, it feels hot and gets hotter as the reaction progresses....(c,f,h)

A spontaneous reaction is taking place in a flask. You notice the formation of gas bubbles intensifies as the reaction progresses....(c,d,I)

A solid in a closed flask begins to melt. (You can consider this a phase change.)....(b,d,g)

A liquid begins to appear on the inside of a closed flask. At first glance before the liquid began to appear, you might have thought the flask was empty. (You can consider this a phase change.)....(a,e,h)

Explanation:

Now it is necessary here to state the equation for ∆G

∆G= ∆H-T∆S

The values of ∆G depends on the relative values of ∆H, T and ∆S.

When heat is evolved by a system, ∆H is negative, when heat is absorbed by a system, ∆H is positive.

When gases are evolved, ∆S is positive, when gases turn to liquids or solids ∆S is negative.

Let us also recall that, for the melting process ∆S positive ( solid changes to liquid), ∆H is positive(energy is absorbed) and T increases( the substance is heated). Hence ∆G is negative

For the condensation process; ∆H is negative (heat is evolved), ∆S is negative (gas changes to liquid) and T is decreased hence ∆G is positive.

5 0

2 years ago

NH4NO3, whose heat of solution is 25.7 kJ/mol, is one substance that can be used in cold pack. If the goal is to decrease the te

makvit [3.9K]

Answer:

There are necessaries 35,2g of NH₄NO₃ per 100,0g of water to decrease the temperature of the solution from 25,0°C to 5,0°C

Explanation:

To decrease the temperature of the solution there are necessaries:

4,184J/g°C×(5,0°C-25,0°C)×(100,0g+X) = -Y

8368J + 83,68J/gX = Y (1)

Where x are grams of NH₄NO₃ you need to add and Y is the energy that you need to decrease the heat.

Also, the energy Y will be:

Y = 25700J/mol× $\frac{1mol}{80,043g}$ X

Y = 321J/g X (2)

Replacing (2) in (1)

8368J + 83,68J/g X = 321J/g X

8363J = 237,32J/gX

X = 35,2g

Thus, there are necessaries 35,2g of NH₄NO₃ per 100,0g of water to decrease the temperature of the solution from 25,0°C to 5,0°C

I hope it helps!

6 0

2 years ago

Exactly 17.0 mL of a H2SO4 solution was required to neutralize 45.0 mL of 0.235 M NaOH. What was the concentration of the H2SO4

aleksandr82 [10.1K]

Answer:

Molarity for the sulfuric acid is 0.622 M

Explanation:

When we neutralize an acid with a base, molarity of both . both volume are the same. The formula is:

M acid . volume of acid = M base . volume of base

M acid = unknown

Volume of acid = 17 mL

Volume of base = 45 mL

M base = 0.235 M

Therefore, we replace: M acid . 17 mL = 0.235 M . 45 mL

M acid = (0.235 M . 45 mL) / 17 mL

M acid = 0.622 M

6 0

2 years ago

How much heat must be removed from 25.0g of steam at 118.0C in order to form ice at 15C

NemiM [27]

Answer:

-10778.95 J heat must be removed in order to form the ice at 15 °C.

Explanation:

Given data:

mass of steam = 25 g

Initial temperature = 118 °C

Final temperature = 15 °C

Heat released = ?

Solution:

Formula:

q = m . c . ΔT

we know that specific heat of water is 4.186 J/g.°C

ΔT = final temperature - initial temperature

ΔT = 15 °C - 118 °C

ΔT = -103 °C

now we will put the values in formula

q = m . c . ΔT

q = 25 g × 4.186 J/g.°C × -103 °C

q = -10778.95 J

so, -10778.95 J heat must be removed in order to form the ice at 15 °C.

3 0

2 years ago