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2 years ago

Which kind of investigations allow for the control of variables?

Chemistry

2 answers:

KATRIN_1 [288]2 years ago

6 0

Answer: The answer would be B. Hope this helps.

Explanation:

Monica [59]2 years ago

4 0

Answer:

Explanation:

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10.

Andru [333]

Answer: 1.8 moles Fe and 2.7 moles $CO_2$ are produced.

Explanation:

The balanced chemical reaction is:

$Fe_2O_3+3CO\rightarrow 2Fe+3CO_2$

According to stoichiometry :

3 moles of $CO$ require 1 mole of $Fe_2O_3$

Thus 2.7 moles of $CO$ will require= $\frac{1}{3}\times 2.7=0.9moles$ of $Fe_2O_3$

Thus $CO$ is the limiting reagent as it limits the formation of product and $Fe_2O_3$ is the excess reagent.

As 3 moles of $CO$ give = 2 moles of $Fe$ and 3 moles of $CO_2$

Thus 2.7 moles of $CO$ will give = $\frac{2}{3}\times 2.7=1.8moles$ of $Fe$ and $\frac{3}{3}\times 2.7=2.7moles$ of $CO_2$

Thus 1.8 moles Fe and 2.7 moles $CO_2$ are produced.

7 0

2 years ago

How many moles of water react with 0.946 mol of nitrogen dioxide

VARVARA [1.3K]

the answer is
2.7 moles

5 0

3 years ago

The sink-float method is often used to identify the type of glass material found at crime scenes by determining its density.

Olegator [25]

Answer:

Glass that will sink

alkali zinc borosilicate with a density of 2.57 g/mL in a solution with a density of 2.46 g/mL

potash soda lead with a density of 3.05 g/mL in a solution with a density of 1.65 g/mL

Glass that will float

soda borosilicate with a density of 2.27 g/mL in a solution with a density of 2.62 g/mL

alkali strontium with a density of 2.26 g/mL in a solution with a density of 2.34 g/mL

Glass that will not sink or float

potash borosilicate with a density of 2.16 g/mL in a solution with a density of 2.16 g/mL

Explanation:

Density is the property of matter that states the ratio of the amount of matter, its mass, to the space occupied by it, its volume.

So, the mathematical expression for the density is:

density = mass / volume

By comparing the density of a material with the density of a liquid, you will be able to determine whether object will float, sink, or do neither when immersed in the liquid.

The greater the density of an object the more it will try to sink in the liquid.

As you must have experienced many times an inflatable ball (whose density is very low) will float in water, but a stone (whose denisty is greater) will sink in water.

The flotation condition may be summarized by:

When the density of the object < density of the liquid, the object will float

When the density of the object = density of the liquid: the object will neither float nor sink

When the density of the object > density of the liquid: the object will sink.

Glass that will sink

alkali zinc borosilicate with a density of 2.57 g/mL in a solution with a density of 2.46 g/mL, because 2.57 > 2.46.

potash soda lead with a density of 3.05 g/mL in a solution with a density of 1.65 g/mL, because 3.05 > 1.65.

Glass that will float

soda borosilicate with a density of 2.27 g/mL in a solution with a density of 2.62 g/mL, because 2.27 < 2.62.

alkali strontium with a density of 2.26 g/mL in a solution with a density of 2.34 g/mL, because 2.26 < 2.34.

Glass that will not sink or float

potash borosilicate with a density of 2.16 g/mL in a solution with a density of 2.16 g/mL, because 2.16 = 2.16

8 0

3 years ago

If the formation of NaCl proceeds according to the following equation and change in enthalpy, what is the reaction and change in

Sergio039 [100]

Answer:

2NaCl → 2Na + Cl₂, ΔH = 822 kJ

Explanation:

The chemical equation for the formation of NaCl is:

Na + (1/2) Cl₂ → NaCl , ΔH = - 411 kJ

That equation means that 1 mole of NaCl is formed by the reaction of 1 mole of Na and 1/2 mole of Cl₂, with a release of energy of 411 kJ.

The decomposition of NaCl is the inverse of the formation reaction; thus, you swift products and reactants and inverse the sign of the change in enthalpy:

NaCl → Na + 1/2 Cl₂, ΔH = 411 kJ

Since you want the decomposition of 2 moles you multiply the equation and the ΔH by 2:

2NaCl → 2Na + Cl₂, ΔH = 822 kJ ← answer

3 0

2 years ago

Water is different from other substances

alekssr [168]

It's more dense as a liquid than as a solid. That's why ice can float in water. The answer is B.

5 0

2 years ago

Read 2 more answers