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3 years ago

Which of the following elements is a Group 1 metal? A. He B. F C. Ca D. Cs

Chemistry

1 answer:

timurjin [86]3 years ago

6 0

It would be D. Cs

Because if you look at a periodic table the first column are the group 1 metals - I included a picture of group 1

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Which one of the following descriptions relating to nuclear reactions is correct?

monitta

Answer: option D - The total number of nucleons changes.

Explanation:

Nuclear Reaction is best described as a process such as the fission of an atomic nucleus, or the fusion of one or more atomic nuclei and / or subatomic particles in which the NUMBER of PROTONS and / or NEUTRONS in a nucleus CHANGES; the reaction products may contain a different element or a different isotope of the same element.

Note that the NUCLEONS refers to ONE of the subatomic particles of the atomic nucleus, i.e. a PROTON or a NEUTRON.

So, in a Nuclear reaction, the total number of nucleons changes.

4 0

3 years ago

Which element has the smallest atomic radius? Fluorine, Iron, Phosphorous, Potassium

Ivahew [28]

Answer:

actually answer should be helium

7 0

3 years ago

Read 2 more answers

How many chlorine atoms are there in 12.2 g of ccl4? How many chlorine atoms are there in 12.2 of ? 4.77×1022 atoms?

mash [69]

Answer:- $1.91*10^2^3Cl$ atoms.

Solution:- We have been given the grams of carbon tetrachloride and asked to calculate the number of atoms of chlorine. It is a three step conversion problem. In the first we convert the grams of carbon tetrachloride to moles of it. In second step we convert moles of carbon tetrachloride to moles of chlorine and in the third step we convert the moles of chlorine to atoms of chlorine.

For grams to mole conversion we need the molar mass of the compound. Molar mass of carbon tetrachloride is 153.82 grams per mol. If we look at the formula of carbon tetrachloride then four chlorine are present in it. It means 1 mol of carbon tetrachloride has four moles of chlorine. The calculations are as follows:

$12.2gCCl_4(\frac{1molCCl_4}{153.82gCCl_4})(\frac{4molCl}{1molCCl_4})(\frac{6.02*10^2^3Clatoms}{1molCl})$

= $1.91*10^2^3Cl$ atoms

So, there are $1.91*10^2^3Cl$ atoms in 12.2 grams of $CCl_4$ .

6 0

3 years ago

Read 2 more answers

U HUCUS 13 HUU

mario62 [17]

Answer:

The correct answer is a the central core and is composed of protons and neutrons.

Explanation:

Nucleus is present in the center of an atom.Nucleus contain positively charged particle proton along with neutron which is neutral.

Due to the the presence of protons nucleus contain positive(+ve) charge.

4 0

3 years ago

Dihydrogen dioxide decomposes into water and oxygen gas. Calculate the amounts requested if 1.34 moles of dihydrogen dioxide rea

a_sh-v [17]

Answers:

a. Moles of oxygen formed: 0.670 mol

b. Moles of water formed: 1.34 mol

c. Mass of water formed: 24.1 g

d. Mass of oxygen formed: 21.4 g

Explanation:

Dihdyrogen dioxide is the chemical name for a compound made of two hydrogen atoms and two oxide atoms, i.e. H₂O₂, which is also known as hydrogen peroxide or oxygenated water.

The decomposition reaction of dihydrogen dioxide into water and oxygen gas is represented by the balanced chemical equation:

$2H_2O_2(l)\rightarrow 2H_2O(l)+O_2(g)$

The mole ratios derived from that balanced chemical equation are:

2 mol H₂O₂ : 2 mol H₂O : 1 mol O₂

a. Moles of oxygen formed

Set the proportion using the theoretical mole ratio of H₂O₂ to O₂ and the amount of moles of dyhydrogen dioxide that react:

$2\text{ mol }H_2O_2/1\text{ mol }O_2=1.34\text{ mol }H_2O_2/x$

When you solve for x, you get:

x = 1.34 mol H₂O₂ × 1 mol O₂ / 2 mol H₂O₂ = 0.670 mol O₂

b. Moles of water formed

Set the proportion using the theoretical mole ratio of H₂O₂ to H₂O and the amount of moles of dyhydrogen dioxide that react:

$2\text{ mol }H_2O_2/2\text{ mol }H_2O=1.34\text{ mol }H_2O_2/x$

When you solve for x, you get:

x = 1.34 mol H₂O₂ × 2 mol H₂O / 2 mol H₂O₂ = 1.34 mol H₂O

c. Mass of water formed

Using the number of moles of water calculated in the part b., you calculate the mass of water formed, in grams, using the molar mass of water:

Molar mass of water = 18.015 g/mol

Number of moles = mass in grams / molar mass

⇒ mass in grams = number of moles × molar mass

⇒ mass in grams = 1.34 mol × 18.015 g/mol = 24.1 g

d. Mass of oxygen formed

Using the number of moles of oxygen determined in the part a., you calculate the mass in grams using the molar mass of O₂.

Molar mass of O₂ = 32.00 g/mol

mass = molar mass × number of moles

mass = 32.00 g/mol × 0.670 mol = 21.4 g.

5 0

3 years ago