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2 years ago

Determine the number of 3s electrons in na.

1 answer:

7 0

Use the atomic number (Z) of the element and determine the electron configuration.

Z for Na is 11 => 11 electrons.

=> electron configuration = 1s2 2s2 2p6 3s

So, there you can count 5 s electrons: 2 in 1s, 2 in 2s and 1 in 3s).

The questions asks only for the 3s electrons, so the answer is one 3s electron.

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A solution of cough syrup contains 5.00% active ingredient by volume. If the total volume of the bottle is 11.0 mL , how many mi

Marta_Voda [28]

All you need to do is change 5% into a decimal which would be 5/100 = .05
then multiply the decimal by the total volume to get the amount of active ingredients in ml
.05 * 56ml = 2.8 ml of active ingredient.

Hope that helps!

4 0

2 years ago

Read 2 more answers

Two electrons in an atom are separated by 1.5 ✕ 10-10 m, the typical size of an atom. what is the electric force between them?

densk [106]

Given two electrons with charge of 1.5x10^-10 m

The electostatic force between them is determined by this formula:

F = kq1q2/r^2

where

k = 9x10^9
q1 = q2 = 1.5x10^-10
r = 2.82x10^-15

F = 9x10^9 * (1.5x10^-10)^2 / 2.82x10^-15
= 71808.51

4 0

2 years ago

Read 2 more answers

Which postulate of Dalton's theory is consistent with the following observation concerning the weights of reactants and products

hram777 [196]

Answer: This illustrates law of conservation of mass.

Explanation:

Dalton's theory is based on mainly two laws which are law of conservation of mass and law of constant proportion.

Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.

This also means that total mass on the reactant side must be equal to the total mass on the product side.

The chemical equation for the decomposition of calcium carbonate follows:

$CaCO_3\rightarrow CaO+CO_2$

We are given:

Mass of calcium carbonate = 100 grams

Mass of calcium oxide = 56 grams

Mass of carbon dioxide = 44 grams

Total mass on reactant side = 100 g

Total mass on product side = 56 + 44 = 100 g

As, the total mass on reactant side is equal to the total mass on product side.

Thus, this illustrates law of conservation of mass.

6 0

2 years ago

The standard molar heat of fusion of ice is 6020 j/mol. calculate q, w, and ∆e for melting 1.00 mol of ice at 0◦c and 1.00 atm p

zysi [14]

Answer : q = 6020 J, w = -6020 J, Δe = 0

Solution : Given,

Molar heat of fusion of ice = 6020 J/mole

Number of moles = 1 mole

Pressure = 1 atm

Molar heat of fusion : It is defined as the amount of energy required to melt 1 mole of a substance at its melting point. There is no temperature change.

The relation between heat and molar heat of fusion is,

$q=\Delta H_{fusion}(\frac{Mass}{\text{ Molar mass}})$ (in terms of mass)

or, $q=\Delta H_{fusion}\times Moles$ (in terms of moles)

Now we have to calculate the value of q.

$q=6020J/mole\times 1Mole=6020J$

When temperature is constant then the system behaves isothermally and Δe is a temperature dependent variable.

So, the value of $\Delta e=0$

Now we have to calculate the value of w.

Formula used : $\Delta e=q+w$

where, q is heat required, w is work done and $\Delta e$ is internal energy.

Now put all the given values in above formula, we get

$0=6020J+w$

w = -6020 J

Therefore, q = 6020 J, w = -6020 J, Δe = 0

3 0

2 years ago

Perform the following calculations and give your answer with the correct number of significant figures:

Arte-miy333 [17]

When multiplying numbers, the term with the least significant digits gives how many significant digits will be in the answer. 2.995 has the least with 4 "sig figs", so the answer will have 4 significant digits as well:

2.995/0.16685 = 17.9502547198
 ↑↑ ↑↑
4 sig figs

So the answer is 17.95.

3 0

2 years ago