1.What is a proton,neutron,and electron?
什么是质子,中子和电子?
The proton is a subatomic particle with an electric charge of +1 elementary charge.
The neutron is a subatomic particle with no net electric charge and a mass slightly larger than that of a proton.
Proton and neutron are usually found in atomic nuclei.
The electron is a subatomic particle carrying a negative electric charge.It has no known components or substructure,and therefore is believed to be an elementary particle.
这种题最好有图解说比较好
2.What is an element,mixture,molecule,and compound?
什么是元素,混合物,分子和化合物
A chemical element is a pure chemical substance consisting of one type of atom.
In chemistry,a mixture is a material system made up by two or more different substance which are (mixed) together but are not combined chemically.
A molecule is an electrically neutral group of at least two atoms in a definite arrangement held together by very strong (covalent) chemical bonds.
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions.
3.What will determine if an object will float if is placed in a fluid?
物体放入液体中能够漂浮在液面上的条件是什么
The buoyancy force is equal or greater than the gravity of the object itself.
4.What is the unit of energy used in electricity bills?How many joules is this equal to?(Can you show your work how you figure this out?)
电费中的单位能量是什么?它相当于多少焦耳?你能写出换算公式么?
Kilowatt per hour【KWH】,1 kwh equals to 3600000 joules.
1 kwh=1 kw * 3600 s(秒) = 3600000 joules
5.The density of water is 1000kg/m3.What is the mass of 10⁻3m3 of water?What is the volume of 21kg of water?
水的密度是1000千克/立方米,10-3立方米的水的质量是多少?21千克水的体积是多少?
m=ρ*V=10⁻3*1000kg=1kg
V=m/ρ=21kg/ (1000kg/m3)=21*10⁻3m3
6.The density of water is 1000kg/m3.An aquarium is filled with water and has dimensions of length 2 m,width 4m,and height 3m.What is the volume of the water?What is the mass of the water in the aquarium?What is the force the water exerts on the bottom of the aquarium?what is the are of the bottom of the aquarium?what is the pressure that the water exerts on the bottom of aquarium?
水的密度是1000kg/立方米,一个盛满水的水缸长2米,宽4米,高3米.求水缸里水的体积是多少?浴缸里的水的质量是多少?水对鱼缸的底的作用力是多少?【中间这句你打错别字了吧】 水对鱼缸的底的压强是多少?