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2 years ago

Which of these substances are elements?

2 answers:

8 0

An element is a species of atom that has the same amounts of electrons and protons in their nuclei. To know which of these substances are elements, we can look it up in the periodic table of elements. The elements are as follows:

1.silicon
2.lead
3.silicone
5.iodine

Andru [333]2 years ago

8 0

Answer is:

1. silicon.

2. lead.

5. iodine.

Silicon (symbol: Si) is an element with atomic number 14 (14 protons).

Lead (Pb) is an element with atomic number 82.

Iodine (I) is an element with atomic number 53.

Silicone is a compound (polymer) made of silicon, oxygen, hydrogen, carbon and other elements.

Quartz is a compound (mineral) made of silicon and oxygen atoms.

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andrey2020 [161]

The equilibrium will shift to the left or the backward reaction since addition of <span>CH3COONa will add more CH3COO- ions to the solution. The formation of reactants are promoted.</span>

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2 years ago

The gram-formula mass of NO2 is defined as the mass of

ch4aika [34]

The correct answer is (1) one mole of NO2.

The gram formula mass is also known as the molar mass and is defined by the mass over one mole of a substance.

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3 years ago

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lions [1.4K]

Answer:

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Explanation:

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2 years ago

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What is the molarity of a 1.44 (m/v)% solution of an HCOOOH (Formic acid)?

AlexFokin [52]

This problem is providing the mass-volume percent of a formic acid solution so its molarity is required and found to be 0.313 M after the following calculations.

<h3>Molarity</h3>

In chemistry, units of concentration provide a measurable understanding of the relationship between the relative amounts of both solute and solvent. In the case of molarity, one must relate moles of solute and liters of solution as follows:

$M=\frac{mol\ solute}{Volume\ solution \ in \ L}$

In such a way, when given this mass-volume percent of 1.44% for the formic acid in the solution, one can assume there is 100 mL of solution and 1.44 g of solute (formic acid), which means one must convert the volume to liters and the mass to moles with:

$mol\ solute=\frac{1.44g}{46.03g/mol} =0.0313mol\\\\Volume\ in \liters: 100mL*\frac{1L}{1000mL}=0.100L$

Finally, we plug in these numbers in the equation for the calculation of molarity:

$M=\frac{0.0313mol}{0.100L}\\\\M=0.313M$

Learn more about molarity: brainly.com/question/10053901

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1 year ago

A nugget of gold has a mass of 28 grams and a volume of 1.45 cubic centimeters. What is the density?

Travka [436]

Answer:

0.01931034

Explanation:

Steps:

ρ = m/v

28 gram

1.45 cubic meter

= 19.310344827586 gram/cubic meter

= 0.019310344827586 kilogram/cubic meter

7 0

2 years ago