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3 years ago

A wave had a frequency of 40 Hz and a wave speed of 100 m/s what is the wavelength

Chemistry

1 answer:

AVprozaik [17]3 years ago

7 0

100m/s divided by 40Hz (cycles) = 2.5 meters per cycle

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When an atom loses electrons it becomes___

murzikaleks [220]

It becomes an ion. An atom that gains a negative electron, it becomes a negative ion. If it loses an electron it becomes a positive ion.

Hope this helps!

8 0

3 years ago

Help please and thank you for who ever

Korolek [52]

Answer:the first one

Explanation:

7 0

3 years ago

Read 2 more answers

1. write the complete chemical symbol for the ion with 14 protons 15 neutrons and 18 electrons

motikmotik

Answer:

1. $Si^{-4}$

2. $Co^{+2}$

Explanation:

An ion is formed when an atom that is said to be neutral gains or losses electrons.

It is thought that a negative ion (anion) is produced as it gains electrons and a positive ion (cation) is formed when it loses an electron.

Atomic number is the total number of protons and electrons in a neutral atom.

From the information

Protons = 14

electron = 18

Net Charge = no of proton - no of electron

= 14 - 18 = -4

Mass number = 14 + 15 = 29

Thus, the chemical symbol = $Si^{-4}$

For ion with 27 proton, 32 neutrons and 25 electrons

Net charge = 27 - 25 = +2

Mass number = 27 + 32 = 59

Thus, the chemical symbol = $Co^{+2}$

6 0

3 years ago

The following reactions can be used to prepare samples of metals. Determine the enthalpy change under standard state conditions

mamaluj [8]

Answer:

a) 62.1 kJ/mol

b) 2.82 kJ/mol

c) 270.91 kJ/mol

d) -851.5 kJ/mol

Explanation:

The enthalpy change for a reaction in standard conditions (ΔH°rxn) can be calculated by:

ΔH°rxn = ∑n*ΔH°f, products - ∑n*ΔH°f, reagents

Where n is the number of moles in the stoichiometry reaction, and ΔH°f is the enthalpy of formation at standard conditions. ΔH°f = 0 for substances formed by only a single element. The values can be found in thermodynamics tables.

a) 2Ag₂O(s) → 4Ag(s) + O₂(g)

ΔH°f, Ag₂O(s) = -31.05 kJ/mol

ΔH°rxn = 0 - (2*(-31.05)) = 62.1 kJ/mol

b) SnO(s) + CO(g) → Sn(s) + CO₂(g)

ΔH°f,SnO(s) = -285.8 kJ/mol

ΔH°f,CO(g) = -110.53 kJ/mol

ΔH°f,CO₂(g) = -393.51 kJ/mol

ΔH°rxn = [-393.51] - [-110.53 - 285.8] = 2.82 kJ/mol

c) Cr₂O₃(s) + 3H₂(g) → 2Cr(s) + 3H₂O(l)

ΔH°f,Cr₂O₃(s) = -1128.4 kJ/mol

ΔH°f,H₂O(l) = -285.83 kJ/mol

ΔH°rxn = [3*(-285.83)] - [( -1128.4)] = 270.91 kJ/mol

d) 2Al(s) + Fe₂O₃(s) → Al₂O₃(s) + 2Fe(s)

ΔH°f,Fe₂O₃(s) = -824.2 kJ/mol

ΔH°f,Al₂O₃(s) = -1675.7 kJ/mol

ΔH°rxn = [-1675.7] - [-824.2] = -851.5 kJ/mol

3 0

3 years ago

In any chemical compound, the elements are always combined in the same proportion by ___.?

irga5000 [103]

Answer is: elements are always combined in the same proportion by mass.

Law of multiple proportions or Dalton's Law said that the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers.

For example, nitrogen(I) oxide N₂O; m(N) : m(O) = 2·14 : 16 = 7 : 4.

Another example, water (H₂O) is made of two hydrogen atoms and one oxygen atom:

m(H) : m(O) = 2·1 : 16 = 1: 8.

6 0

3 years ago

Read 2 more answers