What is the correct formula

How many grams are in a sample of 0.55 mol of K?

Katyanochek1 [597]

The equation you use here is
mass =moles x Mr

So:
Moles of K - 0.55mol
Mr of K - 39.1

Mass= 0.55x39.1 =21.505g

4 0

3 years ago

Which scientist performed the cathode ray experiment leading to the discovery of electrons

SVETLANKA909090 [29]

The scientist that performed the cathode ray experiment leading to the discovery of electrons is J.J. Thomson.

<h3>What is a cathode ray?</h3>

A cathode ray is a tube that contains negatively charged electrode( that is the cathode) which emits electrons when heated at a low pressure.

The cathode ray was used by the scientist, J.J. Thomson to find the ratio of charge to mass (e/m) of the electrons.

Therefore, the scientist that performed the cathode ray experiment leading to the discovery of electrons is J.J. Thomson.

Learn more about electrons here:

brainly.com/question/11316046

#SPJ1

6 0

2 years ago

Oxygen gas is collected over water. The total pressure (the O2 pressure the water vapor pressure) is 736 torr. The temperature o

tigry1 [53]

Answer:

The value of the partial pressure of the oxygen $P_{O_{2} }$ = 690 torr

Explanation:

Total pressure of the mixture of gases = 736 torr

The partial pressure of water vapor = 46 torr

From the law of pressure we know that

Total pressure = The partial pressure of water vapor + The partial pressure of oxygen $O_{2}$

Put the values of pressures in above equation we get,

⇒ 736 = 46 + $P_{O_{2} }$

⇒ $P_{O_{2} }$ = 736 - 46

⇒ $P_{O_{2} }$ = 690 torr

This is the value of the partial pressure of the oxygen.

3 0

3 years ago

Write a net ionic equation for the reaction that occurs when excess hydrochloric acid (aq) and potassium sulfite (aq) are combin

Ket [755]

<u>Answer:</u> The net ionic equation for the given reaction is $2H^+(aq.)+SO_3^{2-}(aq.)\rightarrow H_2O(l)+SO_2(g)$

<u>Explanation:</u>

Net ionic equation of any reaction does not include any spectator ions.

Spectator ions are the ions which do not get involved in a chemical equation. It is also defined as the ions that are found on both the sides of the chemical reaction when it is present in ionic form.

The chemical equation for the reaction of hydrochloric acid and potassium sulfite is given as:

$2HCl(aq.)+K_2SO_3(aq.)\rightarrow 2KCl(aq.)+SO_2(g)+H_2O(l)$

Ionic form of the above equation follows:

$2H^+(aq.)+2Cl^-(aq.)+2K^+(aq.)+SO_3^{2-}(aq.)\rightarrow 2K^+(aq.)+2Cl^-(aq.)+SO_2(g)+H_2O(l)$

As, potassium and chloride ions are present on both the sides of the reaction, thus, it will not be present in the net ionic equation.

The net ionic equation for the above reaction follows:

$2H^+(aq.)+SO_3^{2-}(aq.)\rightarrow SO_2(g)+H_2O(l)$

Hence, the net ionic equation for the given reaction is written above.

7 0

3 years ago

An 8 oz. bottle of energy drink contains 6.0 g of protein, 2.0 g of fat, and 16.3 g of carbohydrate. The fuel value of this ener

valina [46]

<u>Answer:</u> The correct option is d) 460 kJ

<u>Explanation:</u>

We are given:

Content of fat in energy drink = 2.0 g

Content of protein in energy drink = 6.0 g

Content of carbohydrate in energy drink = 16.3 g

Also,

The fuel value of fat = 38 kJ/g

The fuel value of protein = 17 kJ/g

The fuel value of carbohydrate = 17 kJ/g

So, the fuel value of the energy drink will be:

Total fuel value = $(2.0g\times 38 kJ/g)+(6.0g\times 17 kJ/g)+(16.3g\times 17 kJ/g)$

Total fuel value = $[76+102+277]=460kJ$

Hence, the correct option is d) 460 kJ

4 0

3 years ago