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3 years ago

Select the correct answer from each drop-down menu.

Chemistry

1 answer:

postnew [5]3 years ago

8 0

Answer:

Among the different types of scientific knowledge hypotheses are likely to be modified or discarded most frequently. Long ago in the 1600's scientists discarded the phlogiston theory because the new evidence didnt support it.

Explanation:

Hypothesis is the assumption of something possible or impossible to draw a consequence and is provisionally established as the basis for an investigation and which can confirm or deny its validity. For this reason, within scientific research, hypotheses are so important and so changeable that they are modified or discarded more frequently within scientific knowledge.

Based on a work by Johann Joachim Becher, the German scientist Georg Ernst Stahl created the phlogiston theory that said combustion occurred with certain materials because they had an “element” or a common flammable principle that was released at the time of burning . This theory was abandoned because there was no evidence, even through scientific experiments, to prove that this theory is true.

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Fruit juice when boiled taste sweeter than sucrose because

irina1246 [14]

Answer :see explanation

Explanation:

the sweet carbohydrate in fruit is not sucrose , it is fructose.

and fructose tastes sweeter than sucrose

fructose and glucose minus water equals sucrose

and fructose is sweeter than glucose

6 0

2 years ago

The reaction between iron(II) oxide and carbon monoxide produces iron and carbon dioxide. How many moles of iron can be obtained

aleksandrvk [35]

Answer:

1.5 moles of Fe produced.

Explanation:

Given data:

Moles of FeO react = 1.50 mol

Moles of iron produced = ?

Solution:

Chemical equation:

FeO + CO → Fe + CO₂

Now we will compare the moles of ironoxide with iron.

FeO : Fe

1 : 1

1.5 : 1.5

Thus from 1.5 moles of FeO 1.5 moles of Fe are produced.

5 0

3 years ago

TIMED!!

ASHA 777 [7]

Answer:

Hey mate hope its help you........

4 0

3 years ago

A 50.00 g sample of an unknown metal is heated to 45.00°C. It is then placed in a coffee-cup calorimeter filled with water. The

V125BC [204]

Taking into account the definition of calorimetry, the specific heat of metal is 0.165 $\frac{cal}{gC}$ .

<h3>Definition of calorimetry</h3>

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).

So, the equation that allows to calculate heat exchanges is:

Q = c× m× ΔT

where:

Q is the heat exchanged by a body of mass m.
C is the specific heat substance.
ΔT is the temperature variation.

<h3>Specific heat capacity of the metal</h3>

In this case, you know:

For metal:

Mass of metal = 50 g
Initial temperature of metal= 45 °C
Final temperature of metal= 11.08 ºC
Specific heat of metal= ?

For water:

Mass of water = 250 g
Initial temperature of water= 10 ºC
Final temperature of water= 11.08 ºC
Specific heat of water = 1.035 $\frac{cal}{gC}$

Replacing in the expression to calculate heat exchanges:

For metal: Qmetal= Specific heat of metal× 50 g× (11.08 C - 45 C)

For water: Qwater= 1.035 $\frac{cal}{gC}$ × 250 g× (11.08 C - 10 C)

If two isolated bodies or systems exchange energy in the form of heat, the quantity received by one of them is equal to the quantity transferred by the other body. That is, the total energy exchanged remains constant, it is conserved.

Then, the heat that the gold gives up will be equal to the heat that the water receives. Therefore:

- Qmetal = + Qwater

- Specific heat of metal× 50 g× (11.08 C - 45 C)= 1.035 $\frac{cal}{gC}$ × 250 g× (11.08 C - 10 C)

Solving:

- Specific heat of metal× 50 g× (-33.92 C)= 1.035 $\frac{cal}{gC}$ × 250 g× 1.08 C

Specific heat of metal× 1696 g×C= 279.45 cal

Specific heat of metal= $\frac{279.45 cal}{1696 gC}$