Please help .. I’m really stuck

Answer:

Explanation:

The percentage error of a certain measurement can be found by using the formula

[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\ [/tex]

From the question

actual density = 7.80 g/cm³

error = 7.30 - 7.80 = 0.5

We have

[tex]p(\%) = \frac{0.5}{7.8} \times 100 \\ = 6.410256...[/tex]

We have the final answer as

Hope this helps you

Answer:

Explanation:

125 cm3 -> 0.125 L

M = no. mole / volume (L)

M = 0.25 / 0.125 = 2 M

Answer:

70g Na

Explanation:

The sodium reacts with water as follows:

2Na + 2H2O → 2NaOH + H2

Where 2 moles of Na produce 1 mole of H2.

To solve this question we must find the moles of H2. With the balanced equation we can find the moles of Na and its mass as follows:

Moles H2:

PV = nRT; n = PV/RT

Where P is pressure = 1atm,

V is volume = 34L,

R is gas constant = 0.082atmL/molK

T is absolute temperature = 273.15K = 0°C

Replacing:

n = 1atm*34L/0.082atmL/molK*273.15K

n = 1.52 moles H2

Moles Na:

1.52 moles H2 * (2mol Na / 1mol H2) = 3.04 moles Na

Mass Na-Molar mass: 22.99g/mol-

3.04 moles Na * (22.99g / mol) =

Answer:

7

Explanation:

took test

Answer:

the amount of trials in an experiment

Answer:

I think it's impure . Hope this helps you

Answer:

I think is pure but not 100% pure.

Answer: Out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.

Explanation:

A change that leads to the change in chemical composition of a substance is called a chemical change.

For example, [tex]2NH_{3} \rightarrow N_{2} + 3H_{2}[/tex]

Here, bond between the reactant atoms nitrogen and hydrogen is broken down.

On the other hand, bond connecting the products that is [tex]N_{2}[/tex] and [tex]H_{2}[/tex] is formed.

Thus,, we can conclude that out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.

Answer:

As we know that alkalis react with oil to form soap. As our skin contains oil so when we touch strong alkalis, a reaction takes place and the soapy solution is formed. Hence we should wear gloves.

Answer:

As we know that alkalis react with oil to form soap. As our skin contains oil so when we touch strong alkalis, a reaction takes place and the soapy solution is formed. Hence we should wear gloves.

Explanation:

it from internet

Answer:

High amount of humidity

Explanation:

This is especially common in the Caribbean, where hot temperatures very moisture and warm air provide near-ideal circumstances for hurricane formation, as assessed by the Saffir-Simpson classification and the Power Distribution Index.

"Hurricanes may originate everywhere in the Atlantic basin, from the subtropical central Atlantic to the Gulf coast. However, in order to make this all the way to the West Coast of the United States, the storms must pass over a lengthy length of sea water which is far too small to support hurricanes.

The storm strength is influenced by a lot of factors. Due to world warms and increase in the amount of humidity.

What is causing the increase in storm strength?

Studies has shown due too the warming of the world, hurricanes and other tropical cyclones are said to be more stronger.

This is due to the fact that warmer water gives more of the energy that boast storms. A rise in stronger hurricanes is due to warming never ending.

Learn more about storm strength from

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Answer:

2 XE + 1 AB. --> 1 AE2 + 2 XB

Above equation is now balanced

Answer:

use the prefix trans-

When naming a molecule, we indicate that the carbons on either side of the double bond are pointing in opposite directions by adding a prefix (-trans) in the name of the molecule.

IUPAC nomenclature of organic compounds refers to the systematic approach taken for the nomenclature of organic compounds as per the recommendation of the International Union of Pure and Applied Chemistry.

If alkenes have two different substituents at each end of the C=C then they can exist as stereoisomers (as geometric isomers).

This is because there is restricted rotation of the double bond due to the pi bond which means they don't readily interconvert.

Therefore, When naming a molecule, we indicate that the carbons on either side of the double bond are pointing in opposite directions by adding a prefix (-trans) in the name of the molecule.

Learn more about IUPAC Nomenclature, here:

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Answer:

As the kinetic energy of the gaseous solute increases, its molecules have a greater tendency to escape the attraction of the solvent molecules and return to the gas phase. Therefore, the solubility of a gas decreases as the temperature increases.

Explanation:

As the kinetic energy of the gaseous solute increases, its molecules have a greater tendency to escape the attraction of the solvent molecules and return to the gas phase. Therefore, the solubility of a gas decreases as the temperature increases

Answer:

B

Explanation:

Answer:

here hope it helps

Explanation:

covalent bonds

When the amount of gas in a container is increased, the volume increases. Lussac's law states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature.

Answer:

Nitrogen

Explanation:

According to the Periodic Table, the atom with a mass is 16 but the Atomic number is 7 for Nitrogen. That means that Nitrogen is an isotope.

Answer:

The combustion of methane or octane is exothermic; it releases energy. CH4 + 2 O2 → CO2 + 2 H2O + energy The energies of the products are lower than the energiies of the reactants

Answer:

1.395M NaOH

Explanation:

Sodium hydroxide, NaOH, reacts with nitric acid, HNO3, as follows:

NaOH + HNO3 → NaNO3 + H2O

Where 1mol of NaOH reacts with 1mol of HNO3

To solve this question we must find the concentration of the titrant. With the concentration and the needed acid we can find the moles of HNO3 added = moles NaOH in the solution. With the moles of NaOH and its volume we can find its concentration as follows:

HNO3 concentration:

10.00mol/L HNO3 * (125.0mL/500.0mL) = 2.500M HNO3

Moles HNO3 = Moles NaOH:

16.74mL = 0.01674L*(2.500mol/L) = 0.04185 moles HNO3 = Moles NaOH

Concentration NaOH:

0.04185 moles / 0.0300L =

1.395M NaOH

The equation is balanced.

The number of P atoms in the reactant side is 4 and the number of P atoms in the product side is also 4.

The number of O atoms in the reactant side is 16 and the number of O atoms in the product side is also 16.

The number of H atoms in the reactant side is 12 and the number of H atoms in the product side is also 12.

These results are in accordance with the law of conservation of mass.

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Answer:

270. mL

General Formulas and Concepts:

Acid-Base Titrations

Dilution: M₁V₁ = M₂V₂

Explanation:

Step 1: Define

Identify

[Given] V₂ = 629.1 mL

[Given] M₂ = 11.2 M

[Given] M₁ = 26.1 M

[Solve] V₁

Step 2: Find Stock Volume

Step 3: Check

Follow sig fig rules and round. We are given 3 sig figs as our lowest.

269.959 mL ≈ 270. mL

For this one u can work out the amount of moles in h2co3 by using moles=mass/mr(of h2co3 is 52)

so 16/62=0.258moles then u use the equation

number of particle = moles × 6.02×10^23

=0.258×6.02 ×10^23

=1.55×10^23 molecules.

hope this helps

The maximum height of an object, given the initial launch angle and initial velocity is found with:

h = v2 is in2θi 2g

h = v i 2 sin 2 ⁡ θ i 2 g.

Answer: C. The number of collisions of gas particles decreases

Explanation: As temperature decreases so does everything else same with increase.

When the number of particles of a gas decreases the pressure of the gas increases.

In a container containing has molecules, they move about freely in the container but the pressure it exerts on its container depends increase of decrease of the has molecules by volume.

If the volume of a container is decreased, the gas molecules have less space in which to move around. As a result, they will strike the walls of the container more often and the pressure increases.

Therefore, when the number of particles of a gas decreases the pressure of the gas increases.

Learn more about gases here:

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Answer:

Elements make up a compound.

The question is incomplete, the complete question is:

A curium-245 nucleus is hit with a neutron and changes as shown by the equation. Complete the equation by filling in the missing parts.

[tex]_{96}^{245}\textrm{Cm}+_0^1\textrm{n}\rightarrow _{42}^{103}\textrm{Mo}+_{r}^{q}\textrm{p}+3_0^1\textrm{n}[/tex]

Answer: The complete equation formed is [tex]_{96}^{245}\textrm{Cm}+_0^1\textrm{n}\rightarrow _{42}^{103}\textrm{Mo}+_{54}^{140}\textrm{Xe}+3_0^1\textrm{n}[/tex]

Explanation:

The general representation of an isotope is given as:

[rex]_Z^A\textrm{X}[/tex]

where,

A is the mass number, Z is the atomic number and X is the symbol of the element

In a nuclear reaction, total atomic number and total mass number on either side of the reaction remains the same

For the given chemical reaction:

[tex]_{96}^{245}\textrm{Cm}+_0^1\textrm{n}\rightarrow _{42}^{103}\textrm{Mo}+_{r}^{q}\textrm{p}+3_0^1\textrm{n}[/tex]

On the reactant side:

Total atomic number = [96 + 0] = 96

Total mass number = [245 + 1] = 246

On the product side:

Total atomic number = [42 + r + 0] = 42 + r

Total mass number = [103 + q + 3] = 106 + q

Calculating for 'r' and 'q', we get:

[tex]96= 42 + r\\\\r=96-42=54[/tex]

[tex]246 = 106+q\\\\q=246-106=140[/tex]

Thus, the missing isotope is [tex]_{54}^{140}\textrm{Xe}[/tex]

Hence, the complete equation formed is [tex]_{96}^{245}\textrm{Cm}+_0^1\textrm{n}\rightarrow _{42}^{103}\textrm{Mo}+_{54}^{140}\textrm{Xe}+3_0^1\textrm{n}[/tex]

Answer: try 140 52 xe

Explanation:

Answer:

option no. C is correct

an electron in the 3d

Answer:

D. Al(s) + O₂(g) → Al₂O₃(s)

Explanation:

Aluminum is a solid metal, so it is written as Al(s).

Oxygen is a diatomic gas, so we write this compound as O₂(g).

Aluminum oxide has the formula Al₂O₃ because in oxides the oxidation number of oxygen atom is -2 and for aluminum, the oxidation number is 3. Thus, we write this compound as Al₂O₃(s).

Now, we have to found the chemical equation in which the reactants (left side) are Al(s) and O₂(g) while the product (right side) is Al₂O₃(s). From the options, we can see that the correct is (D):

Al(s) + O₂(g) → Al₂O₃(s)

Answer:

Deposition

this is the process of a substance changing its state from gas to solid. Solid to gas is known as sublimation