Answer:
Explanation:
Na react with H2O to form NAOH
2 Na+2H2O....................2NAOH + H2
Ca react with water and form calcium hydroxide
Ca + 2H2O........................Ca(OH)2
Mg react with water and form Magnesium hydroxide
Mg +2H2O .........................Mg(OH)2 however this coating of mg(oh)2 prevent it from further reaction
Fe react with water and form ferric hydride
3Fe +H2O.......................2 FeH +FeO
copper do not react with water
I would say developed technologies which somehow were lost
like the stone age: the stone hammer, who used that afterwards in the roman empire era and stuff?
Answer:
The volume of the piece of iron is 5.18dL.
Explanation:
The density (ρ) is equal to the mass (m) divided the volume (V).

If we rearrange it, we have:

To express the volume in dL we will need the following relations:
- 1 dL = 0.1 L
- 1 kg = 10³ g
- 1 cm³ = 1 mL
- 1mL = 10⁻³L
Then,

Finally,

1. C
2. D (I’m not entirely sure)
3.energy can neither be created nor destroyed, only change forms.
4. C
5. A
6. C
I’ve researched and tried to answer these questions correctly.
Answer:
The correct answer is - the number of days the rainwater stands in the jars.
Explanation:
The independent variable or the manipulating variable is a variable in a research or study is the variable which affects the dependent variable or the variable that is going to measure in the study.
In the study, variables that recieves the treatment and changed in every subject are independent variables and in this study number of days the rainwater standing in various jars that might affect the growth of the bacteria in rainwater.