How many o atoms are in Zn(ClO3)2?

Match these items.

dolphi86 [110]

g - Measurement of Mass

m² - Measurement of Area

m³ - Measurement of Volume

km- Measurement of Length

5 0

3 years ago

A. When calcium metal reacts with water, the gas evolved will not catch fire, but the same gas evolved on Potassium metal to wat

Phoenix [80]

Answer:

a. Due to the evolved hydrogen from potassium to water reaction being able to reach the flash point of the reaction temperature

b. Non-metal

The molecular formula is N₂O₃

Explanation:

a. The heat of the reaction between calcium and water is given as follows

Ca + 2 H₂O → H₂ + Ca(OH)₂ ΔH = -431.15 kJ which is exothermic, Entropy = -125.29 J/K

The heat of the reaction between potassium and water is given as follows

2 k + 2 H₂O → 2 KOH + H₂ ΔH = -393.15 kJ Entropy = 44.91 J/K

Therefore, the reaction between potassium and water occurs more vigorously than the reaction between calcium and water such that the flash point for the released hydrogen gas is reached in the case of potassium

b. The acidic oxides are oxides of metals or non-metals that react with water to produce an acid

Given the valence of the oxide which is +3, the oxide can be aluminium, Al or nitrogen, N, however, Al₂O₃ behaves both as an acid and a base, therefore, the likely candidate is nitrogen, which shows that X is a non-metal

The molecular formula is therefore;

N₂O₃

3 0

3 years ago

3. You measure a cube and determine that its sides are 0.65m. You place the cube on a mass scale and determine that this cube ha

amid [387]

The density of the cube in-

Kg/m³= 38.234 kg/m³

g/mL= 0.038234 g/mL

Explanation:

We know that volume of the cube equals m ³

Where “m” equals side of the cube

Given data-

Side of the cube=0.65m

mass of the cube= 10,500 gm

We know that 1000gm= 1 kg

Hence, 10,500 gm= 10.5 kg

Volume of the cube= (0.65)³

∴ Volume= 0.274625 m ³

We know that density = mass/volume

⇒Substituting the value of mass and volume, we get-

⇒Density= 10.5/0.274625= 38.234 kg/m³

We know that 1 kg/m³= 0.001 g/mL

Hence 38.234 kg/m³ would equal 0.038234 g/mL

Hence the density of the cube is 38.234 kg/m³ and 0.038234 g/mL

7 0

3 years ago

a) A water sample (density=1.00g/mL, S=0.28g/kg) contains Ca(2+) at a concentration of 42 mg/kg. Calculate the molarity of the i

natali 33 [55]

Answer : The molarity of the ion is $1.05\times 10^{-3}M$

Explanation : Given,

Density of sample = 1.00 g/mL

Concentration of $Ca^{2+}$ = 42 mg/kg

First we have to calculate the volume of sample.

Let us assume that the mass of sample be 1 kg or 1000 g.

$Density=\frac{Mass}{Volume}$

$1.00g/mL=\frac{1000g}{Volume}$

$Volume=\frac{1000g}{1.00g/mL}$

$Volume=1000mL=1L$ (1 L = 1000 mL)

Now we have to calculate the moles of $Ca^{2+}$

As we are given that,

Mass of $Ca^{2+}$ in 1 kg of sample = 42 mg = 0.042 g

Molar mass of Ca = 40 g/mole

$\text{Moles of }Ca^{2+}=\frac{\text{Mass of }Ca^{2+}}{\text{Molar mass of }Ca^{2+}}=\frac{0.042g}{40g/mol}=1.05\times 10^{-3}mol$

Now we have to calculate the molarity of the ion.

$\text{Molarity}=\frac{\text{Moles of }Ca^{2+}}{\text{Volume of sample}}$

$\text{Molarity}=\frac{1.05\times 10^{-3}mol}{1L}=1.05\times 10^{-3}mol/L=1.05\times 10^{-3}M$

Therefore, the molarity of the ion is $1.05\times 10^{-3}M$

8 0

3 years ago

Calculate the enthalpy change, ∆H in kJ, for the reaction H2O(s) → H2(g) + 1/2O2(g). Use the following information: : +279.9 kJ

Delvig [45]

Answer:

+ 291.9 kJ

Solution:

The equation given is as;

H₂O ₍s₎ → H₂ ₍g₎ + 1/2 O₂ ₍g₎ ΔH = ?

First, as we know the heat of formation of H₂O ₍l₎ is,

H₂ ₍g₎ + 1/2 O₂ ₍g₎ → H₂O ₍l₎ ΔH = - 285.9 kJ

Now, reversing the equation will reverse the sign of heat as,

H₂O ₍l₎ → H₂ ₍g₎ + 1/2 O₂ ₍g₎ ΔH = + 285.9 kJ

Also, we know that,

H₂O ₍s₎ → H₂O ₍l) ΔH = + 6.0 kJ

Now, adding last two equations,

H₂O ₍l₎ → H₂ ₍g₎ + 1/2 O₂ ₍g₎ ΔH = + 285.9 kJ

H₂O ₍s₎ → H₂O ₍l) ΔH = + 6.0 kJ

-----------------------------------------------------------------------------

H₂O ₍s₎ → H₂ ₍g₎ + 1/2 O₂ ₍g₎ ΔH = + 291.9 kJ

4 0

3 years ago