What is sublimation and what type change is this?

What are the uses of the metal Magnesium?

Kitty [74]

Answer:

use of sterile injections for clearanti bodies

Explanation:

6 0

2 years ago

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The theater director offered every member of the drama one vote for which play they preferred to perform. The director found tha

irakobra [83]

<h2>ANSWER:</h2>

Yes, in this group both events "Oddems Family" and "Thirteenth Night" are mutually exclusive.

<h3>Explanation:</h3>

Mutually exclusive is an statistical term which means the probability of occurrence of two separate event at the same time is zero. It means two events can not be occurred simultaneously.

For example, if we roll the deck ant the probability of coming 1 and 6 at the same time is zero and both events do not depends upon each others occurrence.

Hence only one drama can run in theater at one time. So they are mutually exclusive events.

3 0

3 years ago

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A 1.555-g sample of baking soda decomposes with heat to produce 0.991 g Na2CO3. Refer to Example Exercise 14.l and show the calc

Sunny_sXe [5.5K]

Answer:

a) 101%

b)59.7%

Explanation:

The equation for the thermal decomposition of baking soda is shown;

2NaHCO3 → Na2CO3 + H2O + CO2

Number of moles of baking soda= mass/molar mass= 1.555g/84.007 g/mol = 0.0185 moles

From the reaction equation;

2 moles of baking soda yields 1 mole of sodium carbonate

0.0185 moles of baking soda will yield = 0.0185 moles ×1 /2 = 9.25 ×10^-3 moles of sodium carbonate.

Therefore, mass of sodium carbonate= 9.25 ×10^-3 moles × 106gmol-1= 0.9805 g of sodium carbonate. This is the theoretical yield of sodium carbonate.

%yield = actual yield/theoretical yield ×100

% yield = 0.991/0.9805 ×100

%yield = 101%

Since ;

2NaHCO3 → Na2CO3 + H2O + CO2

And H2O + CO2 ---> H2CO3

Hence I can write, 2NaHCO3 → Na2CO3 + H2CO3

Molar mass of H2CO3= 62.03 gmol-1

Molar mass of baking soda= 84 gmol-1

Therefore, mass of baking soda=

0.325/62.03 × 2 × 84 = 0.88 g of NaHCO3

% of NaHCO3= 0.88/1.473 × 100 = 59.7%

7 0

3 years ago

2Ni(OH) → Ni2O + H2O <br> How many moles of water forms from 4.20 mol of nickel (I) hydroxide?

butalik [34]

Answer:

2.1 moles of water formed.

Explanation:

Given data:

Moles of water formed = ?

Moles of Ni(OH) = 4.20 mol

Solution:

Chemical equation:

2Ni(OH) → Ni₂O + H₂O

Now we will compare the moles of Ni(OH) with water.

Ni(OH) : H₂O

2 : 1

4.20 : 1/2×4.20 = 2.1 mol

2.1 moles of water formed.

5 0

2 years ago

Determining Density and Using Density to Determine Volume or Mass

Shalnov [3]

corrected question:

Determining Density and Using Density to Determine Volume or Mass

(a) Calculate the density of mercury if 1.00 × 10 g occupies a volume of 7.36 cm³

(b) Calculate the volume of 65.0 g of liquid methanol (wood alcohol) if its density is 0.791 g/mL.

(c) What is the mass in grams of a cube of gold (density = 19.32 g/cm) if the length of the cube is 2.00 cm?

(d) Calculate the density of a 374.5-g sample of copper if it has a volume of 41.8 cm³ A student needs 15.0 g of ethanol for an experiment. If the density of ethanol is 0.789 g/mL, how many milliliters of ethanol are needed? What is the mass, in grams, of 25.0 mL of mercury (density = 13.6 g/mL)?

Answer:

density = $\frac{mass}{volume}$

ρ=m/v ,m=ρv, v=m/ρ

(a)m=1*10g , v=7.36cm³

ρ=10/7.36 =1.36g/cm³

(b) m=65g, ρ=0.791 g/mL.

v= 65/0.791 =82.17g/mL

(c) ρ=19.32g/cm³, l=2cm, v=l³=8cm³

m=19..32*8=154.56g/cm³

(d) mass of copper=374.5g , v=41.8cm³

ρ=374.5/41.8 =8.96g/cm³

mass of ethanol=15g, density of ethanol=0.789g/mL

v=15/0.789 =19.01mL

volume of mecury=25mL, density of mercury=13.6g/mL

m=25*13.6=340g

4 0

3 years ago