A hypothesis MUST be supported by the results. True or false

Dalton theorized that atoms are indivisible and that all atoms of an element are identical. Scientists now know that

malfutka [58]

This is easy the answer is c

8 0

4 years ago

A 500 mL hypertonic saline solution is labeled as consisting of 5.21 % w/w NaCl. Given that the density of salt water is 1.02 g/

kicyunya [14]

Answer: The molarity of saline solution is 0.909 M

Explanation:

We are given:

5.21 w/w % NaCl

This means that 5.21 grams of NaCl is present in 100 grams of solution

To calculate mass of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of solution = 1.02 g/mL

Mass of solution = 100 g

Putting values in above equation, we get:

$1.02g/mL=\frac{100g}{\text{Volume of solution}}\\\\\text{Volume of solution}=\frac{100g}{1.02g/mL}=98.04mL$

To calculate the moalrity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}$

Given mass of NaCl = 5.21 g

Molar mass of NaCl = 58.44 g/mol

Volume of solution = 98.04 mL

Putting values in above equation, we get:

$\text{Molarity of solution}=\frac{5.21\times 1000}{58.44g/mol\times 98.04}\\\\\text{Molarity of solution}=0.909M$

Hence, the molarity of saline solution is 0.909 M

3 0

3 years ago

A chemist mixes 1.00 g CuCl2 with an excess of (NH4)2HPO4 in dilute aqueous solution . He measures the evolution of 670 J of hea

kaheart [24]

Answer:

$\Delta H$ will be 90054 J

Explanation:

Number of moles = (mass)/(molar mass)

Molar mass of $CuCl_{2}$ = 134.45 g/mol

So, 1.00 g of $CuCl_{2}$ = $\frac{1.00}{134.45}mol$ of $CuCl_{2}$ = 0.00744 mol of $CuCl_{2}$

0.00744 mol of $CuCl_{2}$ produces 670 J of heat

So, 1 mol of $CuCl_{2}$ produces $\frac{670}{0.00744}J$ of heat or 90054 J of heat

4 0

4 years ago

Phosgene is formed from carbon monoxide and chlorine. At 611 oC, Kc is approximately 16.5 M-1 or L/mol. Calculate Kp (in atm-1)

defon

Answer:

Kp is 0.228/atm

Explanation:

This is the reaction:

CO + Cl₂ → CCl₂O

1 mol of carbon monoxide and 1 mol of chlorine produce 1 mol of phosgene.

Formula for Kp which derivates from Kc is:

Kp = Kc (R.T)ⁿᵇ ⁻ ⁿᵃ

Δп = nb (moles in the products) - nₐ(moles in the reactants)

Δп = 1 - 2 = -1

T is T° in K → T°C + 273 = 611°C +273 = 884K

R → Universal constant gas → 0.082 L.atm/mol.K

We replace the data: Kp = 16.5 L/mol (0.082 . 884K)⁻¹ → 0.228/atm

5 0

4 years ago

If a star is shown ti be 33.11 trillion killometers away , how many light year would that be

adoni [48]

Use proportions.

1 lightyear = 9.4605284 trillion kilometers
x light years ≈ 33.31 trillion kilometers

33.31/9.46 = x/1
3.50 ≈ x

8 0

3 years ago