How many significant figures are in the mass 3.0047 g?

Why does H2O have a lower melting point than MgO

Vesnalui [34]

Answer:

Magnesium Oxide (MgO) has a higher melting point than Sodium Chloride (NaCl) which is around 2,800 degrees Celcius. This is because its Mg2+ and O2- ions have a greater number of charges, and so form stronger ionic bonds, than the Na+ and Cl– ions in Sodium Chloride.

4 0

3 years ago

I really need help with this!

Lady bird [3.3K]

Answer:

Explanation:

The answers are all written in the attachment below. Pardon the writing

8 0

3 years ago

To aid in the prevention of tooth decay, it is recommended that drinking water contains 0.900 ppm fluoride (F-). A) How many g o

Romashka-Z-Leto [24]

Answer:

a) 1.740 g of F- must be added to a cylindrical water reservoir

b) Grams of sodium fluoride, NaF, that contain this much fluoride:

3.84 g

Explanation:

Step 1. calculate the volume of the tank:

Volume of cylinder =

$\pi r^{2}h$ ,

Here r = radius of the cylinder = d/2

h = depth = 21.80m

$r=\frac{d}{2}$

$=\frac{3.36x10^{2}}{2}$

= 168 m

Volume =

$=\frac{22\times 168^{2}\times 21.80}{7}$

$=1.93\times 10^{6} m^{3}$

2.Convert ppm to g/m3 and Solve for mass of F-

$1ppm = 1g/m^{3}$

$0.9ppm = 0.9g/m^{3}$

Because both ppm and g/m3 are same quantity .

$g/m^{3} =\frac{mass\ of\ F-(g)}{Volume\ m^{3}}\times 10^{6}$

$0.9 =\frac{mass\ of\ F-}{1.93\times 10^{6} m^{3}}\times 10^{6}$

$mass\ of\ F- =1.740g$

mass of F- required = 1.740 g

3. Apply mole concept to calculate grams of sodium fluoride produced

mass of 1 mole of F2 = 38 g

mass of 1 mole of NaF = 42 g

(from periodic table calculate molar mass)

$2Na+F_{2}\rightarrow 2NaF$

Here 1 mole of F2 produce = 2 mole of NaF

So,

38 g of F2 produce = 2 x 42 g of NaF

38 g of F2 produce = 84 g of NaF

1 g of F2 produce = 84/38 g of NaF

1.74 g F2 produce =

$\frac {84}{38}\times 1.74$

1.74 g F2 produce = 3.84 g of NaF

3.84 g of NaF is produced

3 0

3 years ago

Consider the two electron arrangements for neutral atoms A and B. Are atoms A and B the same element? A - 1s2, 2s2, 2p6, 3s1 B -

iogann1982 [59]

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<h2>Technically yes but no because you have to fill the 3s orbital before the 5s orbital</h2>

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3 0

3 years ago

To draw a Lewis structure for a

liq [111]

40 electrons

Explanation:

The N for silicon tetrachloride, SiCl₄ is 40 electrons. The needed electrons that would be used to complete the lewis structure of the compound is actually 40 electrons. This number of electron will help the compound attain a noble configuration.

The compound SiCl₄ is a covalent one. Here, there is sharing of electrons between two atoms.
In drawing the electron dot formula, one must take into account the Available electrons and the Needed electrons.
The Available electrons are sum of the valence electrons that can be accessed for the bonding. Si has 4 valence electrons, Cl has 7 valence electrons this makes a total of 4 + 7(4 atoms of chlorine), 32 available electrons.
But to make a complete octet like that of noble gases, each atom most have 8 complete outer most electrons. This is the needed number of electrons. Since there are 5 atoms i.e 4 atoms of chlorine and 1 atom of Silicon, the needed electrons will be 5x8 = 40 electrons.

Learn more:

lewis structure : brainly.com/question/6215269

#learnwithBrainly

8 0

4 years ago