What is 9.871 x 10^-3 in standard form? *

Answer:

Explanation:

given

volume=1.85 d m^3

T=27 degree C=27+273 k=300 k

P=750 mmHg

mass of zinc=?

we know that PV=nRT

n=m/M

PV=mRT/M

M for zinc=65.4

PVM=mRT

m=PVM/RT

m=750*1.85*65.4/0.0821*300

m=90742.5/24.63

m=3684

hope this will help u

Answer:

NO3 will produce 2 acids

Answer:

Calcium because group 2 metals are all 2+ cations

Explanation:

Hi, there!!!!

Let me simply clear you..

Yes,The tendency to gain electrons (in nonmetal) decreases when we go down group 17.

The reason for above answer is when we go downwards in periodic table then the atomic size increases with the addition of number of shells and force of attraction between the nucleus and valance shell decreases. The force of attraction between the nucleus and valance shell becomes weaker due to which the force of attracting the electrons gets decreased.

So, we can say that the tendency to gain electrons decreases as we go down in periodic table.

Hope it helps....

Answer:

the concentration in moles per litre of is

Explanation:

Molarity

mark me as a a brainlist answer

Explanation:

Answer: 89.57 %

Hope it helps

Due to common purpose water and development are substitute of one another.

Water and development are substitute of one another because both contribute in the growth of economy of a country and increases life standard of its people. The presence of water causes growth and betterment of the economy that leads to development of the nation so we can say that due to same effect, both are used as a substitute i.e. in place of one another in the process of growth and betterment.

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Answer:

B

Explanation:

Isotopes have the same number of protons but different number of neutrons.

The true statement is,

So, option C is correct one.

The isotopes have different physical properties like freezing point , mass, melting or boiling point etc because they have different mass number .

learn about isotopes,

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Answer:

hexagonal layers slide

Explanation:

The layers in graphite can slide over each other because the forces between them are weak. The delocalised electrons are free to move through the structure, so graphite can conduct electricity.This makes graphite slippery, so it is useful as a lubricant .

i think it's right

hope it helps :)

Answer:

Explanation:

Given:

Amount in calories = 450 calories

Amount in joules = 3.5 × 100 joules

Find:

Computation:

We know that,

1 calories = 4.184 joules

So,

Amount in calories = 450 calories

= 450 × 4.184

= 1,882.8 joules

Amount in joules = 3.5 × 100 joules

=  [3.5 × 100] / 4.184

= 83.652 calories

Answer:

6.05 g

Explanation:

Use the density to convert the volume to a weight.

(5.00 mL) × (1.21 g/mL) = 6.05 g liquid plant food

You will need 6.05 g liquid plant food.

Answer:

These are compounds.

Explanation:

As it is formed by chemically bonding of two elements C ( carbon) and H (hydrogen) .

Answer:

Butane and benzene are both compounds. They contain multiple elements bonded together in a specific ratio. Kerosene and gasoline are mixtures because they are combinations of several compounds. Oxygen is an element because it is made up of only one type of atom.

Explanation:

Answer:together doesn't make water

Explanation:

together doesn't make water

[tex]\huge\red{AnsweR:}[/tex]

I don't want to go anywhere apart from than Nairobi.

[tex]<font color=orange>[/tex]

A. instead

B. only

C. besides

_______________________

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Answer:

1.29* 10^2

Explanation:

multiply them and then round

Answer:

pcl3 is the empirical formula of the compound

Answer:

Ingredients OR tenderising

Explanation:

Answer:

Why is the unit of force called a derived unit? That's because the Newton is defined in terms of other units which are more fundamental. One Newton is the force required to accelerate a mass of one kilogramme at the rate of one metre per second squared.

Answer:

4.30 × 10²⁰ atoms

Explanation:

You need to find out how many moles you have.  First, convert milligrams to grams.

62.5 mg × (1 g)/(1000 mg) = 0.0625 g

Next, use the molar mass to convert from grams to moles.

0.0625 g ÷ 87.62 g/mol = 7.13 × 10⁻⁴ mol

To convert from moles to atoms, you need to use Avogadro's number (6.022 × 10²³).  Avogadro's number is the number of atoms in a mole.

7.13 × 10⁻⁴ mol × 6.022 × 10²³ atoms/mol = 4.296 × 10²⁰ ≈ 4.30 × 10²⁰ atoms

You will have 4.30 × 10²⁰ atoms of strontium.

The number of Strontium atoms are 4.30 × 10²⁰ atoms

Given:

Mass of Strontium = 62.5 mg × (1 g)/(1000 mg) = 0.0625 g

Molar mass of Strontium = 87.62 g/mol

To find:

Moles of Strontium = ?

It is defined as given mass over molar mass.

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}\\\\\text{Number of moles}=\frac{0.0625 g}{87.62 g/mol }\\\\\text{Number of moles}=7.13 * 10^{-4} mol[/tex]

Avogadro's number is the number of atoms in a mole (6.022 * 10²³)

Conversion of moles into atoms:

[tex]7.13 × 10^{-4} mol * 6.022 * 10^{23} atoms/mol \\\\\text{ Sr atoms}= 4.296 * 10^{20} = 4.30 * 10^{20} atoms[/tex]

Thus, Strontium atoms will be 4.30 × 10²⁰ atoms.

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Answer:

[tex]\Large \boxed{\mathrm{A}}[/tex]

Explanation:

Rust formed from iron and oxygen combining is a chemical change, because in a chemical change, the resulting substance(s) will have different properties from the substance(s) before the chemical change.

I cant comment... So is it Right?

Explanation:

Hi there!!

you asked to multiply these all right,

you can simply multiply it ,

=3cm × 4 cm × 1cm

= 12cm^2×1cm (4×3=12)

= 12cm^3 (12×1=12)

Therefore, theanswer is 12 cm^3.

Hope it helps..

Answer:

"Endothermic reaction: In an endothermic reaction, the products are higher in energy than the reactants. Therefore, the change in enthalpy is positive, and heat is absorbed from the surroundings of the reaction."

Explanation:

When enthalpy is positive and delta H is greater than zero, this means that a system absorbed heat. This is called an endothermic reaction. When enthalpy is negative and delta H is less than zero, this means that a system released heat. This is called an exothermic reaction.

The sign of q for an endothermic process is positive because the system is gaining heat. A chemical reaction or physical change is exothermic if heat is released by the system into the surroundings. Because the surroundings are gaining heat from the system, the temperature of the surroundings increases.

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Answer:

C. Experiments test the scientists' ideas.

Explanation:

Experiments test the scientists' ideas. Therefore, the correct option is C.

By testing ideas and hypotheses, experiments are an essential part of the scientific method and aid scientists' understanding of the world. Science uses regulated procedures to detect particular phenomena, track results, and collect data. These studies give researchers a chance to investigate cause-and-effect relationships, detect patterns, and draw conclusions based on the data. Scientists can test their ideas, theories, and predictions by systematically adjusting various factors to see whether experimental results confirm or disprove them.

Therefore, the correct option is C.

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Answer:

3.34 M or 3.34 mol/L

Explanation:

The formula for molarity is moles of solution ÷ liters of solution. So, we have to convert grams into moles and mL to L.

To convert grams to moles, first find the molar mass of CH₃COOH by looking at the atomic mass of each individual element.

C - 2(12.01) = 24.02

H - 4(1.01) = 4.04

O - 2(16.00) = 32.00

= 60.06

Now divide the number of grams by the molar mass.

10.0 g CH₃COOH ÷ 60.06 g = 0.167 mol CH₃COOH

To convert milliliters to liters, divide by 1000.

50.0 mL ÷ 1000 = 0.05 L

Now we can calculate the molarity.

M = moles of solution ÷ liters of solution

= 0.167 mol ÷ 0.05 L

= 3.34 M or 3.34 mol/L

The molarity is 3.34 M.

Hope that helps.

Answer:

The option closest to the percentage yield is option;

d. 81.1

Explanation:

The given chemical equation of the reaction is presented as follows;

CaO (s) + H₂O (l) → Ca(OH)₂

The mass of CaO in the experiment, m = 2.00 g

The volume of water with which the CaO was reacted = Excess volume of water

Number of moles = Mass/(Molar mass)

The mass of Ca(OH)₂ recovered, actual yield = 2.14 g

The molar mass of CaO = 56.0774 g/mol

The number of moles of CaO in the reaction, n₁ = 2.00 g/(56.0774 g/mol ≈ 0.036 moles

The molar mass of Ca(OH)₂ = 74.093 g/mol

The number of moles of Ca(OH)₂ in the reaction, n₂ = 2.14 g/(74.093 g/mol) ≈ 0.029 moles

From the given chemical reaction, one mole of CaO reacts with one mole of H₂O to produce one mole of Ca(OH)₂

Therefore, 0.036 moles of CaO will produce 0.036 moles of Ca(OH)₂

Mass = Number of moles × Molar mass

The mass of 0.036 moles of Ca(OH)₂ ≈ 0.036 moles × 74.093 g/mol = 2.667348 grams

∴ The theoretical yield of Ca(OH)₂ = 2.667348 grams

[tex]Percentage \ yield = \dfrac{Actual \ yield}{Theoretical \ yield} \times 100 \%[/tex]

The percentage yield = (2.14 g)/(2.667348 grams) × 100 = 80.23%

Therefore, the option which is closest is option d. 81.1.

Answer:

7 significant numbers

Complete Question:

In ∆ABC, if sin A = 4/5 and tan A = 4/3, then what is cos A?

Answer:

[tex]cos A= \frac{3}{5}[/tex]

Explanation:

Given

[tex]sin A = 4/5[/tex]

[tex]tan A = 4/3[/tex]

Required

[tex]cos A[/tex]

In trigonometry;

[tex]tanA = \frac{sinA}{cosA}[/tex]

Multiply both sides by cosA

[tex]cos A * tanA = \frac{sinA}{cosA} * cos A[/tex]

[tex]cos A * tanA = sinA[/tex]

Divide both sides by tanA

[tex]\frac{cos A * tanA}{tanA} = \frac{sinA}{tanA}[/tex]

[tex]cos A= \frac{sinA}{tanA}[/tex]

Substitute values for sinA and tanA

[tex]cos A= \frac{4/5}{4/3}[/tex]

[tex]cos A= \frac{4}{5} / \frac{4}{3}[/tex]

[tex]cos A= \frac{4}{5} * \frac{3}{4}[/tex]

[tex]cos A= \frac{4 * 3}{5 * 4}[/tex]

[tex]cos A= \frac{3}{5}[/tex]

Answer:

C

Explanation:

It's the amount of products you get compared to all the reactants you use. It's kind of like economy in that it's profit, and the higher the atom economy the more products/profit you have.

Answer:

C.) The measure of how much of the reactants end up as products in a chemical reaction.

Explanation:

I got it right on founders edtell.