All categories

3 years ago

What are did facts about atomic number 20?

Chemistry

1 answer:

stira [4]3 years ago

3 0

Basic Calcium Facts

Name: Calcium

Atomic Number: 20

Element Symbol: Ca

Group: 2

Period: 4

Block: s

Element Family: Alkaline Earth

Atomic Mass: 40.078(4)

Electron Configuration: [Ar]4s2

Full: 1s22s22p63s23p64s2 (full)

You might be interested in

Which of the following compounds contains the tin (IV) ion? A. SnO2 B. SnCl2 C. Sn2O D. Sn4O3

Zolol [24]

A. SnO2 is the correct answer. I hope this helps

3 0

3 years ago

Read 2 more answers

How are strong acids and strong bases similar?

Lady_Fox [76]

Answer:

An acid or base which strongly conducts electricity contains a large number of ions and is called a strong acid or base and an acid or base which conducts electricity only weakly contains only a few ions and is called a weak acid or base.

5 0

4 years ago

Hydrazine (N2H4) is a fuel used by some spacecraft. It is normally oxidized by N2O4 according to the following equation: N2H4(l)

vitfil [10]

Answer:

The enthalpy of the reaction is coming out to be -380.16 kJ.

Explanation:

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. It is represented as $\Delta H$

The equation used to calculate enthalpy change is of a reaction is:

$\Delta H_{rxn}=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]$

For the given chemical reaction:

$N_2H_4(l)+N_2O_4(g)\rightarrow 2N_2O(g)+2H_2O(g)$

The equation for the enthalpy change of the above reaction is:

$\Delta H_{rxn}=[(2 mol\times \Delta H_f_{(N_2O)})+(2 mol\times\Delta H_f_{(H_2O)} )]-[(1 mol\times \Delta H_f_{(N_2H_4)})+(1 mol\times \Delta H_f_{(N_2O_4)})]$

We are given:

$\Delta H_f_{(N_2O)}=81.6 kJ/mol\\\Delta H_f_{(H_2O)}=-241.8 kJ/mol\\\Delta H_f_{(N_2H_4)}= 50.6 kJ/mol\\\Delta H_f_{(N_2O_4)}=9.16 kJ/mo$

Putting values in above equation, we get:

$\Delta H_{rxn}=[(2 mol\times 81.6 kJ/mol)+2 mol\times -241.8 kJ/mol)]-[(1 mol\times (50.6 kJ/mol))+(1 mol\times (9.16))]\\\\\Delta H_{rxn}=-380.16 kJ$

Hence, the enthalpy of the reaction is coming out to be -380.16 kJ.

6 0

3 years ago

a nurse practitioner orders Medrol to be given 1.5 mg/kg of body weight. if a child weighs 72.6lb and the available stock of Med

Harrizon [31]

Answer is: 2,469 mL give to the child.
The mass m in kilograms (kg) is equal to the mass m in pounds (lb) times 0,45359237: m(child) = 72,6 · 0,045359237 = 32,93 kg.
m(Medrol) = 32,93 kg · 1,5 mg/kg.
m(Medrol) = 49,39 mg.
d(Medrol) = 20,0 mg/mL.
V(Medrol) = m(Medrol) ÷ d(Medrol).
V(Medrol) = 49,39 mg ÷ 20 mg/mL.
V(Medrol) = 2,469 mL.

8 0

3 years ago

Which is the best definition of an ecosystem?

vredina [299]

Answer:

last one is the correct and most suitable option.

Hope it helps!!!

6 0

3 years ago

Read 2 more answers