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3 years ago

7

The testable question in a science investigation reads: “How does the size of a motor affect the speed of the vehicle?” What is

the independent variable in the question?
A) the sizes of motors

B) the brands of motors

C) the varying speeds

D) the types of vehicles

1 answer:

deff fn [24]3 years ago

3 0

The independent variable for this question would be A) the sizes of motors.

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When a student mixes 50 mL of 1.0 M HCl and 50 mL of 1.0 M NaOH in a coffee-cup calorimeter, the temperature of the resultant so

zmey [24]

Answer: 54.4 kJ/mol

Explanation:

First we have to calculate the moles of HCl and NaOH.

$\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=1.0M\times 0.05=0.05mole$

$\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=1.0\times 0.05L=0.05mole$

The balanced chemical reaction will be,

$HCl+NaOH\rightarrow NaCl+H_2O$

From the balanced reaction we conclude that,

As, 1 mole of HCl neutralizes by 1 mole of NaOH

So, 0.05 mole of HCl neutralizes by 0.05 mole of NaOH

Thus, the number of neutralized moles = 0.05 mole

Now we have to calculate the mass of water:

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = $50ml+50ml=100ml$

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 100ml=100g$

Now we have to calculate the heat absorbed during the reaction.

$q=m\times c\times (T_{final}-T_{initial})$

where,

q = heat absorbed = ?

$c$ = specific heat of water = $4.18J/g^oC$

m = mass of water = 100 g

$T_{final}$ = final temperature of water = $27.5^0C$

$T_{initial}$ = initial temperature of metal = $21.0^0C$

Now put all the given values in the above formula, we get:

$q=100g\times 4.18J/g^oC\times (27.5-21.0)^0C$

$q=2719.6J=2.72kJ$

Thus, the heat released during the neutralization = 2.72 KJ

Now we have to calculate the enthalpy of neutralization per mole of $HCl$ :

0.05 moles of $HCl$ releases heat = 2.72 KJ

1 mole of $HCl$ releases heat = $\frac{2.72}{0.05}\times 1=54.4KJ$

Thus the enthalpy change for the reaction in kJ per mol of HCl is 54.4 kJ

6 0

3 years ago

Read 2 more answers

Which of the following are examples of matter?a. heat b. sunlight c. water d. grass e. air

OverLord2011 [107]

Sunlight? air? i’m not sure they could all be matter..

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3 years ago

Calculate the mass, in grams, of 1.2000 mol Mg₃N₂

fredd [130]

So what do you want me to do
Explanation

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2 years ago

What is the mass of 2.071x10^14 molecules of SF2

kolezko [41]

Answer:

Name of molecule Sulfur Difluoride ( SF2)

No of Valence Electrons in the molecule 20

Hybridization of SF2 sp3 hybridization

Bond Angles 98 degrees

Molecular Geometry of SF2 Bent

Explanation:

Sulfur Difluoride is an inorganic molecule made up of one Sulphur atom and two Fluorine atoms. It has a chemical formula of SF2 and can be generated by the reaction of Sulphur Dioxide and Potassium Fluoride or Mercury Fluoride. In this blog post, we will look at the Lewis dot structure of SF2, its molecular geometry and shape.

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3 years ago

What variable represents specific heat in the equation Q = mcAT?

Elan Coil [88]

Answer: A. The variable c

============================================

Explanation:

Q = heat transferred

m = mass

c = specific heat

$\Delta T$ = delta T = change in temperature

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3 years ago