How many significant figures are in the following numbers?<br> a. 0.002849<br> b. 40030

A small cup of water is left out on the counter. Three days later, the water is gone. Which phase change describes what has occu

kupik [55]

I believe that it should be water evaporation

8 0

4 years ago

Read 2 more answers

The mass of an object Is 45 kilograms. It’s weight on earth is—— newtons, and it’s weight on the moon is ——newtons. Gravitationa

Lina20 [59]

Answer:

The weight of the object on earth =441N

Weight of the object on moon = 72N

Explanation:

Weight of a body is the product of its mass and acceleration due to gravity. Acceleration due to gravity varies between planetary bodies. The acceleration due to gravity on earth is 9.8 m/s² while on moon is 1.6m/s² and it goes different for others too.

Weight = Mass * acceleration due to gravity

Weight(e) = weight on earth

Weight (m) = weight on moon

Weight(e) = 45 * 9.8 = 441N

Weight (m) = 45 * 1.6 = 72N

Weight of a body is measured in a unit called Newton(N)

8 0

4 years ago

Consider three unlabeled bottles, each contain small pieces of one of the following metals. - Magnesium - Sodium - Silver The fo

goldfiish [28.3K]

Explanation:

Reagents: Water , 1.0 M HCl, Conc. $HNO_3$

Metal-1 = Magnesium

Metal-2 = Sodium

Metal-3 = Silver

a) Out of these three metals sodium is a soft metal which can be easily cut with help of knife.Sodium metal reacts violently with water to form hydrogen gas and sodium hydroxide.

$Na(s)+H_2O(l)\rightarrow NaOH(aq)+H_2(g)$

b) Out of magnesium and silver, magnesium metal reacts readily with HClto form magnesium chloride and hydrogen gas. Where as silver being noble metal doesn't get attacked by the HCl.

$Mg(s)+2HCl(aq)\rightarrow MgCl_2+H_2$

c) Silver is a noble metal. And noble metals only react with concentrated $HNO_3$ that is nitric acid.

$3Ag(s)+HNO_3(aq)\rightarrow 3AgNO_3(aq)+2H_2O(l)+NO(g)$

d) When few drops of HCl were added to the solution of silver and $HNO_3$ . This will leads to the formation of nascent chloride which reacts with silver metal present in the solution to give silver chloride.

$1HNO_3+3HCL\rightarrow NOCl+2H_2O+2Cl(\text{nascent chloride})$