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3 years ago

HELP ASAP !!!!!!Can someone tell me easy one line definitions of atomic number, mass number, and isotopes

Chemistry

1 answer:

rusak2 [61]3 years ago

5 0

Answer:

Fundamental properties of atoms including atomic number and atomic mass. The atomic number is the number of protons in an atom, and isotopes have the same atomic number but differ in the number of neutrons.

Explanation:

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Suppose of copper(II) acetate is dissolved in of a aqueous solution of sodium chromate. Calculate the final molarity of acetate

uranmaximum [27]

Answer:

0.0714 M for the given variables

Explanation:

The question is missing some data, but one of the original questions regarding this problem provides the following data:

Mass of copper(II) acetate: $m_{(AcO)_2Cu} = 0.972 g$

Volume of the sodium chromate solution: $V_{Na_2CrO_4} = 150.0 mL$

Molarity of the sodium chromate solution: $c_{Na_2CrO_4} = 0.0400 M$

Now, when copper(II) acetate reacts with sodium chromate, an insoluble copper(II) chromate is formed:

$(CH_3COO)_2Cu (aq) + Na_2CrO_4 (aq)\rightarrow 2 CH_3COONa (aq) + CuCrO_4 (s)$

Find moles of each reactant. or copper(II) acetate, divide its mass by the molar mass:

$n_{(AcO)_2Cu} = \frac{0.972 g}{181.63 g/mol} = 0.0053515 mol$

Moles of the sodium chromate solution would be found by multiplying its volume by molarity:

$n_{Na_2CrO_4} = 0.0400 M\cdot 0.1500 L = 0.00600 mol$

Find the limiting reactant. Notice that stoichiometry of this reaction is 1 : 1, so we can compare moles directly. Moles of copper(II) acetate are lower than moles of sodium chromate, so copper(II) acetate is our limiting reactant.

Write the net ionic equation for this reaction:

$Cu^{2+} (aq) + CrO_4^{2-} (aq)\rightarrow CuCrO_4 (s)$

Notice that acetate is the ion spectator. This means it doesn't react, its moles throughout reaction stay the same. We started with:

$n_{(AcO)_2Cu} = 0.0053515 mol$

According to stoichiometry, 1 unit of copper(II) acetate has 2 units of acetate, so moles of acetate are equal to:

$n_{AcO^-} = 2\cdot 0.0053515 mol = 0.010703 mol$

The total volume of this solution doesn't change, so dividing moles of acetate by this volume will yield the molarity of acetate:

$c_{AcO^-} = \frac{0.010703 mol}{0.1500 L} = 0.0714 M$

8 0

4 years ago

2. Calculate the mass of K in 90g of KOH

ValentinkaMS [17]

KOH = 90g

KOH = 57 g/mol

K = 40g/mol

57g/mol contains 90 g

40g/mol will contain?

= 63.15 g

The mass of K is 63.15g

8 0

3 years ago

Complete combustion of 8.10 g of a hydrocarbon produced 25.9 g of CO2 and 9.27 g of H2O. What is the empirical formula for the h

balu736 [363]

CxHy + O2 --> x CO2 + y/2 H2O

Find the moles of CO2 : 18.9g / 44 g/mol = .430 mol CO2 = .430 mol of C in compound

Find the moles of H2O: 5.79g / 18 g/mol = .322 mol H2O = .166 mol of H in compound

Find the mass of C and H in the compound:

.430mol x 12 = 5.16 g C

.166mol x 1g = .166g H

When you add these up they indicate a mass of 5.33 g for the compound, not 5.80g as you stated in the problem.

Therefore it is likely that either the mass of the CO2 or the mass of H20 produced is incorrect (most likely a typo).

In any event, to find the formula, you would take the moles of C and H and convert to a whole number ratio (this is usually done by dividing both of them by the smaller value).

8 0

4 years ago

hen adding a solute to water, the vapor pressure will __________ and the boiling point will __________.

Nina [5.8K]

Answer:

decrease, increase

Explanation:

6 0

3 years ago

A student uses a calorimeter to determine the enthalpy of dissolving for ammonium nitrate. The student fills a calorimeter with

ale4655 [162]

Enthalpy change during the dissolution process = m c ΔT,

here, m = total mass = 475 + 125 = 600 g
c = specific heat of water = 4.18 J/g °C
ΔT = 7.8 - 24 = -16.2 oc (negative sign indicates that temp. has decreases)

Therefore, Enthalpy change during the dissolution = 600 x 4.18 X (-16.2)
= -40630 kJ
(Negative sign indicates that process is endothermic in nature i.e. heat is taken by the system)

Thus, enthalpy of dissolving of the ammonium nitrate is -40630 J/g

7 0

3 years ago