can u pls help me i need the answer ASAP

Answer:

period is a horizontal row of the periodic table. There are seven periods in the periodic table, with each one beginning at the far left.

Explanation:

maaf kalo salah

In model periodic table the atoms are arranged wrt atomic number, there chemical behaviour, and properties.

The horizontal rows of periodic table are known as periods.

The vertical line of periodic table are knows as groups.

Answer:

Pure water contains no ions.  TRUE

Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O+ ] ions.  TRUE

Explanation:

This is the equilibrium for pure water:

2H₂O  ⇄  H₃O⁺  +  OH⁻          Kw

We see that pure water has no Ions. Pure water can not conduct electricity.

Generally ionized water comes from the water tap.

Another feature of pure water is pH.

Definetely pH of pure water is : 7

As pH = 7, [H₃O⁺] = 1×10⁻⁷

Then, [OH⁻] = 1×10⁻⁷

This is reazonable because Kw is 1×10⁻¹⁴ and Kw = [H₃O⁺] . [OH⁻]

In conclussion:

Pure water contains no ions.  TRUE

Pure water contains equal amounts of hydroxide [OH-] and hydronium [H3O+ ] ions.  TRUE

Pure water contains larger amounts of hydroxide [OH-] than hydronium [H3O+] ions.  FALSE

Pure water is an electrolyte. FALSE

Pure water contains smaller amounts of hydroxide [OH-] than hydronium [H3O ] ions. FALSE

Explanation:

that both the plastic & balloon have the same charge

Answer:

The correct answer is MgCO₃.5H₂O.

Explanation:

Based on the given information,

The mass of hydrate of magnesium carbonate given is 15.67 grams, and the mass of anhydrous magnesium carbonate given is 7.58 grams.

Now the mass of water will be,

= 15.67 grams – 7.58 grams

= 8.09 grams

The molecular mass of magnesium carbonate is 84.32 grams, the moles of MgCO₃ can be determined by using the formula,

Number of moles = Mass/Molecular mass

Moles of MgCO₃ = 7.58/84.32

= 0.0898 moles

Similarly, the number of moles of water will be,

Moles of H₂O = 8.099/18.02

= 0.4489 moles

After getting the values, there is a need to choose the smaller value and use it to divide both the values to get the ratio,

MgCO₃ = 0.0898/0.0898 = 1

H₂O = 0.4489/0.0898 = 4.9 or 5

Thus, the molecular formula for the hydrate will be MgCO₃.5H₂O.

Answer:

It would test positive.

1 becasuevof one vvalence shell

Answer:

me too

Explanation:

Answer: It is causing erosion, landslides, and craters. If this keeps up the ice in the artic will eventually be gone

Explanation:

Answer:

11.4

Explanation:

Density = Mass / Volume

Density = 35.4 / 3.11

Density = 11.38263666

As there are more number of digits after the decimal, you can round it to 3 significant figure.

Now, your value will be:

Density = 11.4

Answer:

24.24 g

Explanation:

First we calculate how many moles are there in 300 mL of a 0.234 M solution, using the definition of molarity:

Converting 300 mL to L ⇒ 300 mL / 1000 = 0.300 L

Then we convert 0.78 moles of NH₄F into grams, using its molar mass:

Answer:

The original concentration is "35 mg/ml".

Explanation:

According to the question,

The solution is diluted,

= 1:50

The initial volume,

V1 = 1 ml

Final concentration,

= 0.07 mg

then,

The final volume,

V2 = 500 ml

As we know,

⇒ [tex]V_1N_1=V_2N_2[/tex]

or,

⇒ [tex]N_1=\frac{V_2N_2}{V_1}[/tex]

On substituting the values, we get

⇒       [tex]=\frac{500\times 0.07}{1}[/tex]

⇒       [tex]=\frac{35}{1}[/tex]

⇒       [tex]=35 \ mg/ml[/tex]

A 0.07 mg/mL BHL solution was prepared by performing a 1:500 dilution on a 35 mg/mL solution.

A 1:500 dilution was carried out to prepare a 0.07 mg/mL BHL solution. We can find the concentration of the initial solution using the dilution rule.

It is an equation that relates the concentration and volume of a concentrated and a dilute solution. The mathematical expression is:

C₁ × V₁ = C₂ × V₂

where,

C₁ = C₂ × (V₂/V₁)

C₁ = 0.07 mg/mL × (500/1) = 35 mg/mL

A 0.07 mg/mL BHL solution was prepared by performing a 1:500 dilution on a 35 mg/mL solution.

Learn more about dilution here: https://brainly.com/question/1615979

Answer:

Decomposition of normal salt ( sodium chloride )

Formation of water from hydrogen peroxide.

Combustion of propane

e.t.c

Answer:

Veins

Explanation:

Veins carry blood to the heart while arteries carry away from the heart

Answer:

The correct answer is 1.21 L.

Explanation:

Based on the given information, the reaction will be,

CS2 (l) + 3Cl2 (g) ⇒ CCl4 (l) + S2Cl2 (l)

By using the standard values of the substances, the standard enthalpy of the reaction is,

ΔH° = [(-139.5) + (-58.5) – 0 – (87.3)] kJ/mol

= -285.3 kJ/mol

The amount of heat evolved for 3 moles of chlorine reacted us 285.3 kJ.

Now the number of moles of chlorine needed to react to produce 5.00 kJ is,

= 5.00 kJ × 3 mol Cl2/285.3 kJ

= 0.0526 mol Cl2

Now the volume of chlorine gas at 27degree C and 812 mmHg will be,

Volume = 0.0526 mol Cl2 × 0.0821 Latm/mol K × 300 K/ 1.07 atm

= 1.21 L

Answer:

The correct answer is 40.7 grams.

Explanation:

Based on the given information, the volume of copper sulfate added to the solution is 255 ml or 0.255 L. The molarity of copper sulfate is not given, so let us consider it to be 1 M, which can also be written as 1 moles per liter.

The moles of copper sulfate can be determined by using the formula,

Moles = Molarity * Volume in Liters

Moles of CuSO4 = 1 moles/Liter * 0.255 L

Moles of CuSO4 = 0.255 moles

The mass of CuSO4 added in the solution will be,

Mass of CuSO4 = Moles * Molecular mass

= 0.255 moles * 159.609 grams per mole

= 40.7 grams.

Na3PO4*12H2O + BaCl2*2H2O = Ba3(PO4)2 + NaCl + H2O

add barium chloride to your Na3PO4.12H2O a white precipitate of Ba3(PO4)2 will be formed wrt salt(NaCl) and water(H20) if Na3PO4.12H2O. will be there.

Answer: C2H6O

Explanation: It is C2H6O with a molar mass of 46.07 g/mol.

Answer:17.65 or 18 L

Explanation:

Answer:

1.The substance(s) to the left of the arrow in a chemical equation are called reactants. A reactant is a substance that is present at the start of a chemical reaction. The substance(s) to the right of the arrow are called products

2.The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products

3.The law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. For example, the mass of sodium plus the mass of chlorine that reacts with the sodium equals the mass of the product sodium chloride.

Answer:

molecules take up more space

Answer:

This combination can make a buffer

Explanation:

A buffer is defined as an aqueous mixture of a weak acid and its conjugate base, or vice versa.

In the problem, HF is a weak acid, and its conjugate base is F⁻.

When NaOH reacts with HF, F⁻, Na⁺ and H₂O are produced as follows:

NaOH + HF → F⁻ + Na⁺ + H₂O

As there are initially 0.2mol of HF and 0.1mol NaOH, after the reaction you will have:

0.1mol HF and 0.1mol F⁻. As both, the weak acic and the conjugate base are present:

Answer:

I think it's 1.D

2.C

3.C

my apologies if it's incorrect

Answer:

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im 100% sure

Explanation:

Answer:

[tex]\boxed {\boxed {\sf x\approx 12.0 \ moles \ HCl}}[/tex]

Explanation:

Molarity is a measure of concentration in moles per liter.

[tex]molarity= \frac{moles \ of \ solute}{liters \ of solution}[/tex]

We know the solution has a volume of 7.98 liters and it has a molarity of 1.50 M HCl.

We know 2 values for the variables, but the value for moles of solute is unknown, so we use x.

Substitute the values into the formula.

[tex]1.50 \ mol \ HCl/L=\frac{x}{7.98 \ L}[/tex]

We are trying to solve for x, the moles of solute, so we must isolate the variable. It is being divided by 7.98 liters and the inverse of division is multiplication. Multiply both sides of the equation by 7.98 liters.

[tex]7.98 \ L *1.50 \ mol \ HCl/L=\frac{x}{7.98 \ L} * 7.98 \ L[/tex]

[tex]7.98 \ L *1.50 \ mol \ HCl/L=x[/tex]

The units of liters (L) cancel each other out.

[tex]7.98 *1.50 \ mol \ HCl=x[/tex]

[tex]11.97 \ mol \ HCl=x[/tex]

The original measurements of molarity and volume both have 3 significant figures, so our answer must have the same. For the number we found, that is the tenths place.

The 9 in the hundredth place tells us to round the 1 to a 2. We leave a 0 in the tenths place to ensure there are 3 significant figures.

[tex]12.0 \ mol \ HCl \approx x[/tex]

There are approximately 12.0 moles of solute in the solution.

Explanation:

Respuesta: La masa atómica del carbono (C) es 12 g/mol; para el oxígeno (O) es de 16 g/mol. Esto significa que 6.022 x 1023 átomos de carbono pesan 12 gramos. Según esto, el peso molecular del CO2 es: 12 g/mol [C] + 2 x 16 g/mol [O2] = 44 g/mol

Answer:

An increase in pressure would cause less volume and vice versa. They are inversely proportional.

Explanation:

This is due to Boyle's Law (and because an increase in pressure would increase the force on the container, however, if it's a closed container, it would burst)

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