What type of reaction occurs in a hand warmer?<br> Exothermic<br> Endothermic

What type of bonding occurs in a sample of pure sodium, ? In other words, how is one sodium atom held to another sodium atom? A.

NeX [460]

Answer:

The answer to your question is B. metallic

Explanation:

Covalent bonding is a bond between two nonmetals and the difference in electronegativity is between 0 and 1.7. Sodium could not have this kind of bond because is a metal.

Ionic bonding is a bond between a metal and a nonmetal and the difference of electronegativity is higher than 1.7. Sodium can have this kind of bond it is necessary one nonmetal.

Metallic, sodium has a metallic bond because this bond is characteristic of metals.

4 0

3 years ago

What is the temperature of 0.55 mol of gas at a pressure of 1.5 atm and a volume of 12.6 L ?

Taya2010 [7]

Answer:

The temperature is 419,1 K

Explanation:

We use the formula PV=nRT T=PV/nR

T=1,5 atm x 12,6 L/0,55 mol x 0,082 l atm/K mol

T= 419,0687361 K

3 0

3 years ago

1.

garik1379 [7]

Explanation:

1.

Given parameters:

Frequency of the radiation = 8.4 x 10¹⁴Hz

Unknown:

Energy of the wave = ?

Solution:

The energy of a wave is given by the expression below;

E = hf

E is the energy

h is the Planck's constant = 6.63 x 10⁻³⁴m²kg/s

f is the frequency

Now insert the parameters and solve;

E = 6.63 x 10⁻³⁴m²kg/s x 8.4 x 10¹⁴Hz

E = 5.57 x 10¹ x 10⁻²⁰J

E = 5.57 x 10⁻¹⁹J

2.

Given parameters:

Wavelength = 2.13 x 10⁻¹³m

Unknown:

Frequency of the wave = ?

Solution:

The frequency of a wave can be determined using the expression;

C = f∧

C is the speed of light = 3 x 10⁸m/s

f is the frequency

∧ is the wavelength

f = $\frac{C}{wavelength}$ = $\frac{3 x 10^{8} }{2.13 x 10^{-13} }$ = 1.41 x 10²¹hz

5 0

3 years ago

A sample was prepared by mixing 18. ml of 3.00 x 10^-3 m crystal violet (cv) with 2.00 ml of 0.250 m naoh. calculate the resulti

Aleks [24]

Answer : The resulting concentrations of CV and NaOH are 0.0027 M and 0.025 M respectively.

Explanation :

Step 1 : Find moles of crystal violet and NaOH.

The molarity formula is

$Molarity = \frac{mol}{L}$

Molarity of crystal violet = $3.00 \times 10^{-3} = \frac{mol (CrystalViolet)}{L}$

The volume of crystal violet solution is 18 mL which is 0.018 L.

Moles of crystal violet = $3.00 \times 10^{-3} \times 0.018 = 5.4 \times 10^{-5}$

Moles of crystal violet = 5.4 x 10⁻⁵

Moles of NaOH = $Molarity \times L = 0.250 \times 0.00200 = 5.00 \times 10^{-4}$

Moles of NaOH = 5.00 x 10⁻⁴

Step 2 : Find total volume of the solution

The total volume of the solution after mixing NaOH and crystal violet is

0.018 L + 0.00200 = 0.020 L

Step 3 : Use molarity formula to find final concentrations

Molarity of crystal violet = $\frac{mol(CrystalViolet)}{Total Volume(L) } = \frac{5.4 \times 10^{-5}}{0.020} = 2.7 \times 10^{-3}$

Final concentration of CV = 0.0027 M

Molarity of NaOH= $\frac{mol(NaOH)}{Total Volume(L) } = \frac{5.00 \times 10^{-4}}{0.020} = 0.025 \times 10^{-3}$

NaOH is a strong base and dissociates completely as follows.

$NaOH (aq) \rightarrow Na^{+} (aq) + OH^{-} (aq)$

The mole ratio of NaOH and OH⁻ is 1:1 . Therefore the concentration of OH⁻ is same as that of NaOH.

Concentration of OH⁻ = 0.025 M

8 0

3 years ago

Apart from plants, what other group of organisms photosynthesises?<br>

Licemer1 [7]

Answer:

Plants, algae, and a group of bacteria called cyanobacteria are the only organisms capable of performing photosynthesis

4 0

2 years ago

What type of reaction occurs in a hand warmer? Exothermic Endothermic