66 A student wants to design a controlled experiment to solve the following problem: When placed in a freezer, will hot water or cold water reach 0°C faster?
The student plans to place two containers with equal masses of water (one hot and one cold) in the same freezer in the classroom.
a List three conditions the student should keep constant for the hot-water and cold-water setups when planning this experiment. [3]
b For each condition you name, give a scientific reason why the condition needs to be the same for both the hot-water and cold-water setups

Answer:

The orest one is possible D

Explanation:

Answer:

XZ2

Explanation:

There are different ways in which compounds can be represented. Broadly, we have three different types of formula;

- Structural formular: This shows how th atoms in te compound are connected to each other.

- Molecular formular: This shows the actual number of atoms of element present in the compound

- Empirical Formular: This is the simplest formular of a compound. It basically shows the number of atoms in simple ration to each other.

This question requires us to input the empirical formular;

X2Z4

The ratio of the elements is; 2 : 4 which can be simplified into 1 : 2

This means the empirical formular is XZ2

Answer:

D Nimbostratus

Explanation:

Answer:

Explanation:

A cation with a 2+ charge will make a stronger ionic bond than a cation with a 1+ charge. A larger ion makes a weaker ionic bond because of the greater distance between its electrons and the nucleus of the oppositely charged ion.

Answer:

3

Explanation:

Subscript basically tells you the number of element or ions present in a compound. In this case the subscript of carbon which is 3 denotes that only three carbon atoms is present in the compound.

Answer:

Rusting is an oxidation reaction. The iron reacts with water and oxygen to form hydrated iron(III) oxide, which we see as rust. Unlike rust, which can flake off the surface of iron and steel objects, the layer of aluminium oxide does not flake off.

Explanation:

Answer:

it's easier to look it up

Explanation:

The balanced equation :

LiI(aq) + AgNO₃(aq) --> AgI(s) + LiNO₃(aq)

Given

Word equation

Required

Balanced equation

Solution

There are 3 ways to express a chemical equation:

Skeleton equation for reaction above :

LiI(aq) + AgNO₃(aq) ⇒ AgI(s) + LiNO₃(aq)

If we look at this reaction, all the cations and anions have a charge of 1 (+1 or -1) so the balanced reaction between the skeleton equation and the balanced equation is the same

Answer:

1.58L

Explanation:

Given parameters:

Initial volume  = 1.2L

Initial temperature  = 28.5°C  = 28.5 + 273  = 301.5K

Final temperature  = 125°C  = 125 + 273  = 398K

Unknown:

New volume  = ?

Solution:

Volume and temperature relationship is resolved using the Charles's law.

The law states that "the volume of a fixed mass of a gas varies directly as its absolute temperature if the the pressure is constant".

So;

       [tex]\frac{V1}{T1}[/tex]    = [tex]\frac{V2}{T2}[/tex]  

V1 is the initial volume

T1 is the initial temperature

V2 is the new volume

T2 is the new temperature

             [tex]\frac{1.2}{301.5}[/tex]    = [tex]\frac{V2}{398}[/tex]    

              301.5V2  = 477.6

                       V2  = 1.58L

The mass of an object is the product of its volume and density. The mass of a the object with a volume of 825 cm³ and a density of 13.6 g/cm³ is 11220 g.

Density of substance is the measure of its mass per unit volume. It describes how closely its particles are packed. Density depends on the bond type, temperature and pressure.

Volume of the object is the space occupied by its particles. Volume can be expressed in L, ml, cm³, dm³ etc. Only solids and liquids has a definite volume and the volume of gases is that of the container.

Give that, volume of the object = 825  cm³

density =  13.6 g/cm³

Mass = volume × density

m = 825  cm³ ×  13.6 g/cm³ = 11220 g

Therefore, the mass of the object is 11220 g.

Find more on density:

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Answer:

When the forest burns we will lose a huge amount of oxygen and animals will lose their home.

Explanation:

Answer:

A barium atom would be expected to contain 2 electrons in its outer energy level.

Explanation:

The columns of the periodic table are called groups. There are eighteen groups, numbered from 1 to 18.

The elements of each group have the same number of electrons in their last atomic shell, which is why they have similar chemical properties, because the chemical properties of chemical elements are strongly related to the electrons located in the last atomic shell.

That is, in a group, the chemical properties are very similar, because all the elements of the group have the same number of electrons in their last or last shells.

A barium atom would be expected to contain 2 electrons in its outer energy level.

Answer:

Molarity = 2.4 M

Explanation:

Given data:

Mass of silver fluoride = 12.7 g

Volume of water = 125 mL (125 mL× 1 L /1000 mL = 0.125 L)

Molarity of solution = ?

Solution:

Number of moles of silver fluoride:

Number of moles = mass/molar mass

Number of moles = 12.7 g/ 41.98 g/mol

Number of moles = 0.30 mol

Molarity:

Molarity = number of moles of solute / volume in L

Molarity = 0.30 mol / 0.125 L

Molarity = 2.4 M

Answer: Reactant

Explanation:

In simple wording, Water act as a reactant and it broke or we can say split the larger molecule in the smaller ones, The H and OH bonds are attached to the two products that are formed after the reaction. Another process in which water is used as an important reactant is photosynthesis.

Answer:

hot air rises and expanded the balloon

Explanation:

thats it.

Answer:

2.86L

Explanation:

Given parameters:

V1  = 2.1L

T1  = 200°C  = 200 + 273  = 473K

T 2  = 370°C  = 370 + 273  = 643K

Unknown:

V2  = ?

Solution:

Since pressure is constant, we apply the Charles's law;

           [tex]\frac{V1}{T1}[/tex]   =  [tex]\frac{V2}{T2}[/tex]  

V is volume

T is the temperature

1 is the initial state

2 is the new state

                [tex]\frac{2.1}{473}[/tex]    = [tex]\frac{V2}{643}[/tex]  

                 V2  = 2.86L

Answer:

6.Crust

7. outer core

8.mantle

Answer:

85.155g NH3

Explanation:

Answer:

To some extent, yes

Explanation:

Answer:

Pseudoscience

Explanation:

Predicting the future based solely on the position of the planets is an example of pseudoscience.

Pseudoscience is a body of knowledge that is not based on the scientific method but on some unverifiable/unprovable claims.

Predictions about the future can only be valid if it is based on the scientific method, not just about the position of the planet. The scientific method involves observation, hypothesis formulation, testing of the hypothesis through repeatable experiments, and arriving at conclusion.

Any other statement or belief that is not based on these procedures is said to be pseudoscientific.

Answer:

The answer to your question is pseudoscience.

Explanation:

I took the module 1 exam and got it right, yesterday.

Answer:

HC2H3O2(I) + O2(g) ---> H2O(I) + CO2(g) ΔH= -72.35 kJ

Explanation:

We know that 5.0 g of acetic acid will contain, 5.0g/60 g/mol = 0.083 moles of acetic acid

Now from the reaction equation;

1 mole of acetic acid evolved -871.7 KJ of heat

0.083 moles of acetic acid will evolve 0.083 * -871.7 = -72.35 KJ

For 5.0 g of acetic acid, we can write;

HC2H3O2(I) + O2(g) ---> H2O(I) + CO2(g) ΔH= -72.35 kJ

Answer:

4

Explanation:

The following equation, which depicts the combustion of propane, is given in this question as follows:

C3H8 + 02 → CO2 + H2O

However, this equation is not yet BALANCED because the number of atoms of each element is not the same on the reactant and product side. To balance the equation, we make use of COEFFICIENT to ensure that the number of atoms of each element on both side correlates.

The balanced equation is as follows:

C3H8 + 502 → 3CO2 + 4H2O

Therefore, the coefficient for water (H2O) after balancing the equation is 4.

The study of chemicals is called chemistry.

The correct answer is D.

The equation is not yet BALANCED because the number of atoms of each element is not the same on the reactant and product sides.

To balance the equation, we make use of COEFFICIENT to ensure that the number of atoms of each element on both sides correlates.

After balancing the equation is as follows:

[tex]C_3H_8 + 50_2 → 3CO_2 + 4H_2O[/tex]

Hence, the correct answer is 4 which shows the balanced water.

For more information, refer to the link:-

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Answer:

two moles

There are two moles.

Explanation:

Answer:

Kinetic - Kinetic energy is the energy of motion

Explanation:

Thermal energy - heat energy

Potential energy - energy that is stored

Hope this helped!

Have a supercalifragilisticexpialidocious day!

Explanation:

The equation of the reaction is;

H2O2 + N2H4 → N2 + H2O

Upon balancing the reaction, we have;

N2H4 + 2H2O2 → N2 + 4H2O  

a. How many moles of N2 are formed from 0.0250 moles of N2H4?

From the equation of the reaction;

1 mol of N2H4 produces 1 mol of N2

0.0250 mol of N2H4 would produce x mol of N2

1 = 1

0.0250 = x

x = 0.0250 * 1 / 1 = 0.0250 mol

b. How many moles of H2O2 are required if 1.35 moles of H2O is to be produced?

From the equation of the reaction;

2 mol of H2O2 produces 4 mol of H2O

x mol of H2O2 produces 1.35 mol of H2O

2 = 4

x = 1.35

x = 1.35 * 2 / 4 = 0.675 mol

c. How many moles of H2O are formed if 1.87 moles of N2 is produced?

The relationship between H2O produced and N2 is;

For every 1 mol of N2 produced, 4 mol of H2O is produced

1.87 mol of N2 produced, how many moles of H2O is produced?

1 = 4

1.87 = x

x = 1.87 * 4 / 1 = 7.48 mol