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3 years ago

Weight measures

Chemistry

1 answer:

jasenka [17]3 years ago

5 0

Answer: D) The effect of gravity on an object

Explanation: We're not talking about mass, we're talking about weight. Weight is measured by the force of gravity on a object. For examples, you might be 100 pounds on Earth but 12 pounds on the moon.

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A sample of iron is put into a calorimeter (see sketch at right) that contains of water. The iron sample starts off at and the t

Mariulka [41]

Answer:

Therefore, the specific heat capacity of the iron is 0.567J/g.°C.

Note: The question is incomplete. The complete question is given as follows:

A 59.1 g sample of iron is put into a calorimeter (see sketch attached) that contains 100.0 g of water. The iron sample starts off at 85.0 °C and the temperature of the water starts off at 23.0 °C. When the temperature of the water stops changing it's 27.6 °C. The pressure remains constant at 1 atm.

Calculate the specific heat capacity of iron according to this experiment. Be sure your answer is rounded to the correct number of significant digits

Explanation:

Using the formula of heat, Q = mc∆T

where Q = heat energy (Joules, J), m = mass of a substance (g)

c = specific heat capacity (J/g∙°C), ∆T = change in temperature (°C)

When the hot iron is placed in the water, the temperature of the iron and water attains equilibrium when the temperature stops changing at 27.6 °C. Since it is assumed that heat exchange occurs only between the iron metal and water; Heat lost by Iron = Heat gained by water

mass of iron = 59.1 g, c = ?, Tinitial = 85.0 °C, Tfinal = 27.6 °C

∆T = 85.0 °C - 27.6 °C = 57.4 °C

mass of water = 100.0 g, c = 4.184 J/g∙°C, Tinitial = 23.0 °C, Tfinal = 27.6 °C

∆T = 27.6°C - 23.0°C = 4.6 °C

Substituting the values above in the equation; Heat lost by Iron = Heat gained by water

59.1 g * c * 57.4 °C = 100.0 g * 4.184 J/g.°C * 4.6 °C

c = 0.567 J/g.°C

Therefore, the specific heat capacity of the iron is 0.567 J/g.°C.

5 0

2 years ago

A sample of 87.6 g of carbon is reacted with 136 g of

Vadim26 [7]

Answer:

A. fluorine, 1.79 moles

Explanation:

Given parameters:

Mass of carbon = 87.7g

Mass of fluorine gas = 136g

Unknown:

The limiting reactant and the maximum amount of moles of carbon tetrafluoride that can be produced = ?

Solution:

Equation of the reaction:

C + 2F₂ → CF₄

let us find the number of the moles the given species;

Number of moles = $\frac{mass}{molar mass}$

C; molar mass = 12;

Number of moles = $\frac{87.7}{12}$ = 7.31moles

F; molar mass = 2(19) = 38g/mol

Number of moles = $\frac{136}{38}$ = 3.58moles

So;

From the give reaction:

1 mole of C requires 2 moles of F₂

7.31 moles of C will then require 2 x 7.31 moles of F₂ = 14.62moles

But we have 3.58 moles of the F₂;

Therefore, the reactant in short supply is F₂ and it is the limiting reactant;

So;

2 moles of F₂ will produce mole of CF₄

3.58 moles of F₂ will then produce $\frac{3.58}{2}$ = 1.79moles of CF₄

6 0

3 years ago

Which of the following is a scientific question? O A. How can I make a peach cobbler? O B. What chemicals cause most plants to b

igor_vitrenko [27]

The answer is B. Because think about it, it’s not a scientific fact that brown dogs are better pets, and the best color for your room isn’t it because the answer would be an opinion of someone not a fact. I hope this might help you.

5 0

3 years ago

which atom has a change in oxidation number of -3 in the following redox reaction K2Cr2O7 + H2O +S --> KOH + Cr2O3 +SO2

yaroslaw [1]

You have to calculate the oxidation estates of the atoms in each compound.

I will start with K2Cr2O7 because I believe that Cr is the best candidate to reduce its oxidation number in 3 units.

In K2Cr2O7:

- K has oxidation state of 1+, then K2 has a charge of 2* (1+) = 2+.

- O has oxidation state of 2*, then O7 has a charge of 7* (2-) = 14-.

That makes that Cr2 has charge of 14 - 2 = +12, so each Cr has +12/2 = +6 oxidation state.

In Cr2O3:

- O has oxidation state of 2-, then O3 has charge 3 * (2-) = - 6

- Then, Cr2 has charge 6+, and each Cr has charge 6+ / 2 = 3+.

So, we have seen that Cr reduced its oxidation state in 3 units, from 6+ to 3+.

Answer: Cr has a change in oxidation number of - 3.

6 0

3 years ago

What happens to the number of outermost electrons as you move across a period?

Reika [66]

C The number of outermost electrons increases.

6 0

3 years ago