In the molecule 4H2O2 the number of hydrogen atoms is what

Answer:

ZnC4H10

Explanation:

The empirical formula of a compound refers to the formula that gives the simplest whole number ratio of each atoms of the elements in the compound.

The empirical formula is calculated thus:

The given percentages in the question represent the mass in grams of each element in the compound.

Zinc= 53%, C= 38.9%, H= 8.1% which represents 53g, 38.9g and 8.1g of each element respectively.

Molar Mass of Zn= 65.4 g/mol

Molar Mass of C= 12 g/mol

Molar Mass of H= 1 g/mol

Step 1: Divide the mass of each element by the molar mass given to convert to moles:

Zn= 53/65.4 = 0.81moles

C= 38.9/12 = 3.24moles

H= 8.1/1 = 8.1moles

Step 2: Divide each mole value by the smallest number of moles calculated, which is 0.81moles:

Zn= 0.81/0.81 = 1

C= 3.24/0.81 = 4

H= 8.1/0.81= 10

This is the mole ratio represented in the subscript of each element in the empirical formula:

That is, Zn (1) C (4) H (10)

Empirical formula= ZnC4H10

Answer:

[tex]\large \boxed{350}[/tex]

Explanation:

In multiplication and division problems, the answer can have no more significant figures than the number with the fewest significant figures.

My calculator gives the result:

[tex]\dfrac{4568}{13} = 351.3846154[/tex]

4658 has four significant figures.

     13 has two significant figures.

You must round to two significant figures.

That is, you drop all the digits to the right of the 5 — the red line in Fig. 1 below. You are rounding to the nearest ten.

To round a number to the nearest ten, you look at the number in the ones place (1). See Fig. 2.

If the number to be dropped — the digit in the ones place — is less than 5, you drop the digit in the ones place (Fig. 3). It becomes a zero.

The number in the tens place is a trailing zero. It is not significant.

[tex]\text{The quotient of $\dfrac{4658}{13}$ is $\large \boxed{\mathbf{350}}$}[/tex]

Answer:

[tex]\huge\boxed{\sf D = 7.8 \ g/cm^3}[/tex]

Explanation:

Density = Mass / Volume

Where Mass = 39 g and Volume = 5 cm³

So,

[tex]\sf Density = \frac{39}{5} \\Density = 7.8 g/cm^3[/tex]

Answer:

Answer:

These are two types of indicators which show a solution is either an acid a natural or an alkali solution

Explanation:

Hope this helps :)

Answer:

Explanation:

The density of an object can be found using the formula

From the question

mass of kerosene = 36.4 g

volume of kerosene = 45.6 mL

To find the density substitute the values into the above formula and solve

We have

= 0.7982

We have the final answer as

Hope this helps you

Answer:

True

Explanation:

This is true because no chemical bonding or change was involved only mechanical mixing.

Answer:

The shape of a molecule based on the number of electron pairs on the valence shell of its central atom

Explanation:

The improvement of the Sidgwick-Powell theory came to be known as the Valence Shell Electron Pair Repulsion theory (VSEPR). This theory approaches the determination of molecular shape from the perspective of the number of electron pairs on the valence shell of the central atom in the molecule.

Electron pairs on the valence shells of atoms leads to repulsion. Repulsion between two lone pairs is greater than repulsion between a lone pair and a bond pair which is also greater than repulsion between two bond pairs.

Lone pairs cause more repulsion, hence they distort molecules from the ideal shape predicted based on their electron domain geometry.

Answer: D. the number of protons

Explanation: The number of protons shows you what the Atomic number of an element is on the Periodic table of elements.

The identity of an element is primarily determined by the number of protons it possesses. The Option C.

Each element on the periodic table has a unique number of protons in its nucleus which is referred to as its atomic number. This fundamental property of an element distinguishes it from other elements and determines its place on the periodic table.

While number of neutrons and electrons can vary within an element, it is the number of protons that defines its identity. Thus, the correct answer is C: the number of protons.

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Answer:

The proportionality constant ( Henry’s constant) = 2.32 * 10^-5 M/kPa

Explanation:

Here in this question, we are concerned with calculating the proportionality constant for this gas.

Mathematically, we can get this from Henry law

From Henry law;

Concentration = Henry constant * partial pressure

Thus Henry constant = concentration/partial pressure

Henry constant = 0.00290 M/125 kPa = 2.32 * 10^-5 M/kPa

Answer:

C. Partial charges in water molecules attract the charges in the atoms of the ionic crystal, pulling the atoms off the crystal.

Explanation:

Water consists of partial positive and hydrogen ions and partial negative oxygen ions. The ionic crystals also dissociate into ions when in water.These partial charges and ability of ionic compounds to dissociate in water are the main reason why ionic crystals dissolve in water.

The partial charges in the water molecules form a strong attraction towards the charges in the atoms of ionic crystals. This then pulls the atoms from the crystals and ends up in the dissolution of the ionic crystals.

The percentage of carbon in urea is [CO(NH 2) 2] is 20%

Answer: 0.01 moles (I am guessing)

Explanation:

Firstly, cm3 and ml are equal to one another, therefore 250cm3 can also be written as 250 ml. I Googled and found that ideally, one mole of gas will occupy a volume of 22.4 L (22,400 ml) at s.t.p. 250 ml out of 22,400 ml is 0.01 rounded, therefore I assume that is the answer. About 0.01 mole occupies 250 cm3 at s.t.p.

Answer:

Hope it helps!!!

............

In the Lewis structure, the Ca atom donates its two valence electrons to two F atoms.

The bonding in calcium fluoride (CaF₂) involves the transfer of electrons from calcium (Ca) to fluorine (F), resulting in the formation of ionic bonds.

Each F atom gains one electron to achieve a stable electron configuration of eight electrons in its outermost energy level. The electrostatic attraction between the positively charged Ca ion (Ca²⁺) and the negatively charged F ions (F⁻) holds the compound together.

It's important to note that the diagram represents a simplified 2-dimensional representation of the compound's structure. In reality, the compound adopts a three-dimensional crystal lattice structure, with each Ca ion surrounded by eight F ions and each F ion surrounded by four Ca ions.

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Answer:

The accuracy of the measuring ruler is given as tenth of a centimetre and given that the image above the ruler is measuring in between a tenth of a centimetre, it is therefore measuring at a higher accuracy than the ruler

The least count of the vernier scale =  (Main scale's smallest reading)/(Number of vernier scale divisions)

Where;

Main scale's smallest reading = 0.1 cm

Number of vernier scale divisions = 10

We have;

The least count of the vernier scale =0.1/10 = 0.01

The image above the ruler, (the vernier scale measurement) should therefore measure at hundredth of a centimetre and the value of the measurement given to two places of decimal, 2.XX, as such 2.755 which is of a level of accuracy of a thousandth for the vernier scale would not be correct.

Explanation:

Explanation:

the first question's answer is a

the second question's answer is c

It causes freezing point depression which requires the gasoline to reach a much lower temperature before freezing. Hence, option C is correct.

Whenever a solute is added to a solution/solvent, it leads to depression in the freezing point of that solution/solvent. Depression in the freezing point of a solution on the addition of a solute is a colligative property.

A colligative property is a physical property which depends upon the number of solutes added not on the nature of solutes which means it does not matter whether we are adding 1000 particles of sugar or salt in water, the depression in the freezing point will occur by the same °C. Also, the more a solute is added the more will be the depression at the freezing point.

The formula for depression at the freezing point is mentioned as under:

             Δ T = K x m

where Δ T = freezing point depression;

                 K = cryoscopic constant;

                 m = molality of the solution.

For example, The freezing point of water is 0 °C but as soon as we add a 92 gm solute like NaCl (common salt) in 1000 gm of water, its freezing point will be lower to −3.72 °C.

Hence, option C is correct.

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Answer:

The pH of 500 cm³, 0.2 mol/dm³, Ca(OH₂) is ≈ 13.6

Explanation:

The given parameters are;

Concentration of the calcium hydroxide, Ca(OH₂) = 0.2 mol/dm³

Volume of the calcium hydroxide, Ca(OH₂) = 500 cm³

Given that the calcium hydroxide, Ca(OH₂),  undergoes complete ionization in water, complete dissociation, we have;

Ca(OH₂)  ⇄  Ca²⁺ + 2 OH⁻

Therefore, we have;

2 moles of [OH⁻] for each mole of Ca(OH₂) which gives the concentration of  [OH⁻] as

[OH⁻] = 2 × 0.2 ≈ 0.4 mol/dm³

The pH is given by the formula

pH = 14 + ㏒₁₀ [OH⁻]

pH = 14 + ㏒₁₀ (0.4) = 14 - 0.3979 = 13.6021 ≈ 13.6

The pH of the 500 cm³ 0.2 mol/dm³ Ca(OH₂) ≈ 13.6.

Answer:

Here is it....

Explanation:

Answer:

Reacting hydrogen and oxygen gases to make water

Explanation:

Exothermic means that energy is released into the environment, so let's go through the process of elimination.

Allowing meat to thaw after taking it out of the freezer - NO it is endothermic, and takes energy/heat from the environment to thaw.

Popsicle melting on a warm summer day - NO also endothermic, the opposite of exothermic.

Boiling water in a beaker to convert it to steam - NO because we need to add heat, so it doesn't release any energy.

Rolling a ball up a hill - NO, for a ball to roll up a hill, it needs energy from something else, so it's not exothermic.

Reacting hydrogen and oxygen gases to make water - YES this reaction makes new bonds, which releases energy, so this is exothermic.

Among the following choices reacting hydrogen and oxygen gases to make water is an exothermic reaction as it releases energy as new bonds are formed.

An exothermic reaction is defined as a chemical reaction which involves release of energy in the form of light,heat .In these reactions, energy is transferred from system to surroundings rather than taking energy from surroundings into system as in endothermic reactions.

In an exothermic reaction,change in enthalpy is negative.Therefore, it can be inferred that net amount of energy which is required to start the exothermic reaction is less than the net amount which is released by the reaction.

Examples of exothermic reactions are combustion reactions, detonation of nitroglycerin , neutralization reactions and nuclear fission.

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Answer:

Diamonds

Explanation:

The melting point of sugar is 186C

The melting point of oxygen is -218C

The melting point of diamonds are 4078C

Therefore diamonds have the highest melting point.

You can also think of their structures, as diamonds have a covalent network structure, meaning they are really strong and have a high melting point

Oxygen has a covalent molecular structure

Sugar has a much weaker covalent network structure

Answer:

ipotseeeeeeeeeeeeeeee

Answer:

If mass remains the same while the volume of a substance changes, the density of the substance will also change.

Answer:

BELOW

Explanation:

If mass remains the same while the volume of a substance decreases the density of the substance will increase.

Answer:

rabbit

Explanation:

Answer:

rabbit

Explanation:

the rabbit is the consumer because the sun "produces" the tree and mushroom, the rabbit comes along and eats the mushroom which was produced by the sun.

Answer: 89.57 %

Hope it helps

Answer:

Explanation:

                        N₂(g) + O₂(g) ⇄ 2NO( g )

We shall apply Le Chatelier's principle to see the effect of decrease in volume or increase in concentration on the effect of state of equilibrium in the reaction given .

In this reaction 1 volume of nitrogen gas reacts with 1 volume of oxygen to give 2 volume of NO gas . In total there is no change in volume due to reaction . So when we change the volume , the concentration of reactant and product will affect the rate of forward and reverse reaction . Overall there will be no change in the state of equilibrium . The equilibrium will neither shift to the right nor will shift to the left.

It will remain unchanged .

Answer:

The answer is "6.68 [tex]\frac{ml} {hr}[/tex]".

Explanation:

It's going to be 18.18 kg to turn body mass to kg.  

Size 1mg / kg / hr, therefore = 1 x 18.18

                                               = 18.18 kg / hr  

now we adding 30 mg / ml of dextrose = 30 x 15

                                                                 [tex]=\frac{450mg}{15 ml +150 ml}[/tex]

of dextrose, from 15 ml to 150 ml;  

Therefore, now 450 mg in 165m:    

[tex]= \frac{ 450}{165}\\ \\=2.72 \frac{mg} {ml}[/tex]  

now divide the   18.18 by 2.72:

[tex]=\frac{18.18}{2.72}[/tex]

= 6.68 [tex]\frac{ml} {hr}[/tex]

Answer:

0.60 mL

Explanation:

1. Set up the equation using Vi = MfVf / Mi

Vi = (1.5M · 1L) / 2.5M

2. Solve

1.5 / 2.5 = 0.6