An element x has atomic number 17 and mass number 35 . State the number of neutrons present in element x

An unknown insoluble substance displaced the water shown. It's mass is indicated on the triple beam balance. Mass = A. 694 B. 69

vodka [1.7K]

Answer:

D. 693.8.

Explanation:

The first scale of the triple beam balance indicate that the mass is 600.

The second scale of the triple beam balance indicate that the mass is 690.

The third scale of the triple beam balance indicate that the mass is higher that 693.5 and the scale is near but lower than 694, so the mass = 693.8.c

3 0

3 years ago

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Sterling silver contains silver and copper metals. if a sterling silver chain contains 17.6g of silver and 2.40g of copper, what

Bogdan [553]

Answer:- 0.88

Solution:- Masses of silver and copper metals are given and we are asked to calculate the percentage of silver in the alloy.

mass percent of Ag = $(\frac{mass of Ag}{mass of alloy})*100$

Mass of Ag = 17.6 g

mass of Cu = 2.40 g

mass of alloy = 17.6 g + 2.40 g = 20.0 g

Let's plug in the values in the formula:

mass percentage of Ag = $(\frac{17.6}{20.0})*100$

mass percentage of Ag = 88%

So, the mass percentage of silver in sterling silver is 88% and in decimal form it is 0.88.

7 0

3 years ago

A student is given a 2.002 g sample of unknown acid and is told that it might be butanoic acid, a monoprotic acid (HC4H7O2, equa

Elina [12.6K]

Answer: The identity of the unknown acid is butanoic acid or ascorbic acid.

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}$

Molarity of NaOH solution = 0.570 M

Volume of solution = 39.55 mL

Putting values in above equation, we get:

$0.570M=\frac{\text{Moles of NaOH}\times 1000}{39.55}\\\\\text{Moles of NaOH}=\frac{0.570\times 39.55}{1000}=0.0225mol$

The chemical equation for the reaction of NaOH and monoprotic acid follows:

$NaOH+HX\rightarrow NaX+H_2O$

By Stoichiometry of the reaction:

1 mole of NaOH reacts with 1 mole of HX

So, moles of monoprotic acid = 0.0225 moles

The chemical equation for the reaction of NaOH and diprotic acid follows:

$2NaOH+H_2X\rightarrow 2NaX+2H_2O$

By Stoichiometry of the reaction:

2 moles of NaOH reacts with 1 mole of diprotic acid

So, moles of diprotic acid = $\frac{0.0225}{2}=0.01125moles$

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

For butanoic acid:

Mass of butanoic acid = 2.002 g

Molar mass of butanoic acid = 88 g/mol

Putting values in above equation, we get:

$\text{Moles of butanoic acid}=\frac{2.002g}{88g/mol}=0.02275mol$

For L-tartaric acid:

Mass of L-tartaric acid = 2.002 g

Molar mass of L-tartaric acid = 150 g/mol

Putting values in above equation, we get:

$\text{Moles of L-tartaric acid}=\frac{2.002g}{150g/mol}=0.0133mol$

For ascorbic acid:

Mass of ascorbic acid = 2.002 g

Molar mass of ascorbic acid = 176 g/mol

Putting values in above equation, we get:

$\text{Moles of ascorbic acid}=\frac{2.002g}{176g/mol}=0.01137mol$

As, the number of moles of butanoic acid and ascorbic acid is equal to the number of moles of acid getting neutralized.

Hence, the identity of the unknown acid is butanoic acid or ascorbic acid.

5 0

3 years ago

What salt is formed by the reaction of potassium hydroxide and hydrochloric acid?

Nina [5.8K]

Potassium hydroxide (KOH) is formed when Potassium forms ionic bonds with OH-ions while Potassium Oxide (K2O) is formed when potassium forms ionic bonds with the Oxide (O2-) ions. i.e. This reaction is a neutralization reaction and occurs when an acid (HCl) reacts with a base (KOH).

3 0

3 years ago

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Determine the number of moles of water assicated with the salt.

Nookie1986 [14]

Answer:

Divide the mass of your anhydrous (heated) salt sample by the molar mass of the anhydrous compound to get the number of moles of compound present. In our example, 16 grams / 160 grams per mole = 0.1 moles. Divide the mass of water lost when you heated the salt by the molar mass of water, roughly 18 grams per mole.In order to determine the formula of the hydrate, [Anhydrous Solid⋅xH2O], the number of moles of water per mole of anhydrous solid (x) will be calculated by dividing the number of moles of water by the number of moles of the anhydrous solid (Equation 2.12. 6).

6 0

3 years ago